Anisotropic conductivity connector, conductive paste composition, probe member, and wafer inspection device, and wafer inspecting method

ABSTRACT

Disclosed herein are an anisotropically conductive connector that conductivity of all conductive parts for connection is good, and insulating property between adjacent conductive parts for connection is surely achieved even when the pitch of electrodes as objects of connection is small, and good conductivity is retained over a long period of time even when it is used repeatedly under a high-temperature environment, and applications thereof. The above anisotropically conductive connector is a connector having an elastic anisotropically conductive film, in which a plurality of conductive parts for connection containing conductive particles and extending in a thickness-wise direction of the film have been formed, wherein supposing that the shortest width of each of the conductive parts for connection is W, and the number average particle diameter of the conductive particles is Dn, a value of a ratio W/Dn of the shortest width of the conductive part for connection to the number average particle diameter of the conductive particles falls within a range of 3 to 8, and a coefficient of variation of particle diameter of the conductive particles is at most 50%.

TECHNICAL FIELD

The present invention relates to an anisotropically conductive connectorsuitable for use in conducting electrical inspection of a plurality ofintegrated circuits formed on a wafer in a state of the wafer, aconductive paste composition for obtaining this anisotropicallyconductive connector, a probe member equipped with this anisotropicallyconductive connector, a wafer inspection apparatus equipped with thisprobe member, and a wafer inspection method using this probe member, andparticularly to an anisotropically conductive connector suitable for usein conducting electrical inspection of integrated circuits, which areformed on a wafer, a diameter of which is, for example, 8 inches orgreater and a total number of electrodes to be inspected in theintegrated circuits formed thereon is at least 5,000, in a state of thewafer, a conductive paste composition for obtaining this anisotropicallyconductive connector, a probe member equipped with this anisotropicallyconductive connector, a wafer inspection apparatus equipped with thisprobe member, and a wafer inspection method using this probe member.

BACKGROUND ART

In the production process of semiconductor integrated circuit devices,after a great number of integrated circuits are formed on a wafer formedof, for example, silicon, each of these integrated circuits is generallysubjected to a probe test that basic electrical properties thereof areinspected, thereby sorting defective integrated circuits. This wafer isthen cut, thereby forming semiconductor chips. Such semiconductor chipsare contained and sealed in respective proper packages. Each of thepackaged semiconductor integrated circuit devices is further subjectedto a burn-in test that electrical properties thereof are inspected undera high-temperature environment, thereby sorting semiconductor integratedcircuit devices having latent defects.

In such electrical inspection of integrated circuits, such as the probetest or the burn-in test, a probe member for electrically connectingeach of electrodes to be inspected in an object of inspection to atester is used. As such a probe member, is known a member composed of acircuit board for inspection, on which inspection electrodes have beenformed in accordance with a pattern corresponding to a pattern ofelectrodes to be inspected, and an anisotropically conductive elastomersheet arranged on this circuit board for inspection.

As such anisotropically conductive elastomer sheets, those of variousstructures have heretofore been known. For example, Japanese PatentApplication Laid-Open No. 93393/1976 discloses an anisotropicallyconductive elastomer sheet (hereinafter referred to as “dispersion typeanisotropically conductive elastomer sheet”) obtained by uniformlydispersing metal particles in an elastomer, and Japanese PatentApplication Laid-Open No. 147772/1978 discloses an anisotropicallyconductive elastomer sheet (hereinafter referred to as “unevendistribution type anisotropically conductive elastomer sheet”) obtainedby unevenly distributing conductive magnetic particles in an elastomerto form a great number of conductive parts extending in a thickness-wisedirection thereof and an insulating part for mutually insulating them.Further, Japanese Patent Application Laid-Open No. 250906/1986 disclosesan uneven distribution type anisotropically conductive elastomer sheetwith which a difference in level defined between the surface of eachconductive part and an insulating part is formed.

In the uneven distribution type anisotropically conductive elastomersheet, since the conductive parts are formed in accordance with apattern corresponding to a pattern of electrodes to be inspected of anintegrated circuit to be inspected, it is advantageous compared with thedispersion type anisotropically conductive elastomer sheet in thatelectrical connection between electrodes can be achieved with highreliability even to an integrated circuit small in the arrangement pitchof electrodes to be inspected, i.e., center distance between adjacentelectrodes to be inspected.

In such an uneven distribution type anisotropically conductive elastomersheet, it is necessary to hold and fix it in a particular positionalrelation to a circuit board for inspection and an object of inspectionin an electrically connecting operation to them.

However, the anisotropically conductive elastomer sheet is flexible andeasy to be deformed, and so it is low in handling property. In addition,with the miniaturization or high-density wiring of electric products inrecent years, integrated circuit devices used therein tend to increasein number of electrodes and arrange electrodes at a high density as thearrangement pitch of the electrodes becomes smaller. Therefore, thepositioning and the holding and fixing of the uneven distribution typeanisotropically conductive elastomer sheet are going to be difficultupon its electrical connection to electrodes to be inspected of theobject of inspection.

In the burn-in test on the other hand, there is a problem that even whenthe necessary positioning, and holding and fixing of the unevendistribution type anisotropically conductive elastomer sheet to anintegrated circuit device has been realized once, positional deviationbetween conductive parts of the uneven distribution type anisotropicallyconductive elastomer sheet and electrodes to be inspected of theintegrated circuit device occurs when they are subjected to thermalhysteresis by temperature change, since coefficient of thermal expansionis greatly different between a material (for example, silicon) making upthe integrated circuit device that is the object of inspection, and amaterial (for example, silicone rubber) making up the unevendistribution type anisotropically conductive elastomer sheet, as aresult, the electrically connected state is changed, and thus the stablyconnected state is not retained.

In order to solve such a problem, an anisotropically conductiveconnector composed of a metal-made frame plate having an opening and ananisotropically conductive sheet arranged in the opening of this frameplate and supported at its peripheral edge by an opening edge about theframe plate has been proposed (see Japanese Patent Application Laid-OpenNo. 40224/1999).

This anisotropically conductive connector is generally produced in thefollowing manner.

As illustrated in FIG. 22, a mold for molding an anisotropicallyconductive elastomer sheet composed of a top force 80 and a bottom force85 making a pair therewith is provided, a frame plate 90 having anopening 91 is arranged in alignment in this mold, and a molding materialwith conductive particles exhibiting magnetism dispersed in a polymericsubstance-forming material, which will become an elastic polymericsubstance by a curing treatment, is fed into a region including theopening 91 of the frame plate 90 and an opening edge thereabout to forma molding material layer 95. Here, the conductive particles P containedin the molding material layer 95 are in a state dispersed in the moldingmaterial layer 95.

Both top force 80 and bottom force 85 in the mold respectively havemolding surfaces composed of a plurality of ferromagnetic substancelayers 81 or 86 formed in accordance with a pattern corresponding to apattern of conductive parts of an anisotropically conductive elastomersheet to be molded and non-magnetic substance layers 82 or 87 formed atother portions than the portions at which the ferromagnetic substancelayers 81 or 86 have been respectively formed, and are arranged in sucha manner that their corresponding ferromagnetic substance layers 81 and86 oppose to each other.

A pair of, for example, electromagnets are then arranged on an uppersurface of the top force 80 and a lower surface of the bottom force 85,and the electromagnets are operated, thereby applying a magnetic fieldhaving higher intensity at portions between ferromagnetic substancelayers 81 of the top force 80 and their corresponding ferromagneticsubstance layers 86 of the bottom force 85, i.e., portions to becomeconductive parts, than the other portions, to the molding material layer95 in the thickness-wise direction of the molding material layer 95. Asa result, the conductive particles P dispersed in the molding materiallayer 95 are gathered at the portions where the magnetic field havingthe higher intensity is applied in the molding material layer 95, i.e.,the portions between the ferromagnetic substance layers 81 of the topforce 80 and their corresponding ferromagnetic substance layers 86 ofthe bottom force 85, and further oriented so as to align in thethickness-wise direction of the molding material layer. In this state,the molding material layer 95 is subjected to a curing treatment,whereby an anisotropically conductive elastomer sheet composed of aplurality of conductive parts, in which the conductive particles P arecontained in a state oriented so as to align in the thickness-wisedirection, and an insulating part for mutually insulating theseconductive parts is molded in a state that its peripheral edge has beensupported by the opening edge about the frame plate, thereby producingan anisotropically conductive connector.

According to such an anisotropically conductive connector, it is hard tobe deformed and easy to handle because the anisotropically conductiveelastomer sheet is supported by the metal-made frame plate, and apositioning mark (for example, a hole) is formed in the frame plate inadvance, whereby the positioning and the holding and fixing to anintegrated circuit device can be easily conducted upon an electricallyconnecting operation to the integrated circuit device. In addition, amaterial low in coefficient of thermal expansion is used as a materialfor forming the frame plate, whereby the thermal expansion of theanisotropically conductive sheet is restrained by the frame plate, sothat positional deviation between the conductive parts of the unevendistribution type anisotropically conductive elastomer sheet andelectrodes to be inspected of the integrated circuit device is preventedeven when they are subjected to thermal hysteresis by temperaturechange. As a result, a good electrically connected state can be stablyretained.

By the way, in a probe test conducted for integrated circuits formed ona wafer, a method that a wafer is divided into a plurality of areas, ineach of which 16 or 32 integrated circuits among a great number ofintegrated circuits have been formed, a probe test is collectivelyperformed on all the integrated circuits formed in an area, and theprobe test is successively performed on the integrated circuits formedin other areas has heretofore been adopted.

In recent years, there has been a demand for collectively performing aprobe test on, for example, 64 or 124 integrated circuits, or allintegrated circuits among a great number of integrated circuits formedon a wafer for the purpose of improving inspection efficiency andreducing inspection cost.

In a burn-in test on the other hand, it takes a long time toindividually conduct electrical inspection of a great number ofintegrated circuit devices because each integrated circuit device thatis an object of inspection is fine, and its handling is inconvenient,whereby inspection cost becomes considerably high. From such reasons,there has been proposed a WLBI (Wafer Lebel Burn-in) test in which theburn-in test is collectively performed on a great number of integratedcircuits formed on a wafer in the state of the wafer.

When a wafer that is an object of inspection is of large size of, forexample, at least 8 inches in diameter, and the number of electrodes tobe inspected formed thereon is, for example, at least 5,000,particularly at least 10,000, however, the following problems areinvolved when the above-described anisotropically conductive connectoris applied as a probe member for the probe test or WLBI test, since apitch between electrodes to be inspected in each integrated circuit isextremely small.

Namely, in order to inspect a wafer having a diameter of, for example, 8inches (about 20 cm), it is necessary to use an anisotropicallyconductive elastomer sheet having a diameter of about 8 inches as ananisotropically conductive connector. However, such an anisotropicallyconductive elastomer sheet is large in the whole area, but eachconductive part is fine, and the area proportion of the surfaces of theconductive parts to the whole surface of the anisotropically conductiveelastomer sheet is low. It is therefore extremely difficult to surelyproduce such an anisotropically conductive elastomer sheet.

Since the conductive parts to be formed are fine, and the pitch thereofis extremely small, it is difficult to surely produce an anisotropicallyconductive elastomer sheet having necessary insulating property betweenadjacent conductive parts. This is considered to be due to the followingreasons. Namely, coarse particles having a particle diameterconsiderably greater than the average particle diameter of conductiveparticles used for obtaining the anisotropically conductive elastomersheet are mixed into the conductive particles. Therefore, when amagnetic field is applied to a molding material layer for obtaining theanisotropically conductive elastomer sheet, the coarse particles are notsurely contained into portions to become conductive parts in the moldingmaterial layer, but are gathered in a state extending over both portionsto become conductive parts and portions to become insulating parts. Anelectric resistance value between the resulting conductive partsadjoining each other is thereby lowered. As a result, it is difficult tosufficiently ensure the insulating property between these conductiveparts.

In order to solve such a problem, it is considered to use conductiveparticles having a small average particle diameter. However, the use ofsuch conductive particles involves the following problems.

If the thickness of an anisotropically conductive elastomer sheet iseven, the number of conductive particles arranged in a thickness-wisedirection of the anisotropically conductive elastomer sheet, i.e., thenumber of conductive particles forming a conductive path increases asthe particle diameter of the conductive particles used is smaller. Sincethe total sum of contact resistance among the conductive particles inone conductive path increases as a consequence, it is difficult to formconductive parts having high conductivity.

In addition, when a magnetic field is applied to the molding materiallayer for obtaining the anisotropically conductive elastomer sheet, theconductive particles become harder to move as the particle diameterthereof becomes smaller, so that the conductive particles remain in agreat amount at portions to become the insulating parts in the moldingmaterial layer. After all, it is difficult to sufficiently ensure theinsulating property between the conductive parts. At the same time, itis difficult to form conductive parts having expected conductivitybecause the conductive particles are not sufficiently gathered at theportions to become the conductive parts.

Particles obtained by forming a coating layer formed of ahigh-conductive metal, for example, gold or the like on the surfaces ofcore particles composed of a ferromagnetic substance, for example,nickel or the like, are generally used as the conductive particles inthe anisotropically conductive elastomer sheet. In the WLBI test, theanisotropically conductive elastomer sheet are, at the conductive partsthereof, held with pressure by electrodes to be inspected in a waferthat is an object of inspection and inspection electrodes of the circuitboard for inspection, and exposed to a high-temperature environment fora long period of time in this state. However, when the anisotropicallyconductive elastomer sheet is used repeatedly under such severeconditions, the ferromagnetic substance making up the core particles inthe conductive particles migrates into the high-conductive metal formingthe coating layer, so that the conductivity of the conductive particlesat the surfaces thereof is deteriorated. As a result, contact resistancebetween the conductive particles increases. This phenomenon markedlyoccurs as the particle diameter of the conductive particles becomessmaller because the thickness of the coating layer also becomes smaller.As described above, when the conductive particles having a smallparticle diameter are used, the conductivity of the conductive particlesat the surfaces thereof is deteriorated, and the total sum of contactresistance among the conductive particles in the conductive paths formedmarkedly increases when the anisotropically conductive elastomer sheetis used repeatedly under the high-temperature environment, so that it isimpossible to retain the necessary conductivity.

When the above-described anisotropically conductive connector is used asa prove member for the WLBI test, the following problems are involved.

The coefficient of linear thermal expansion of a material making up thewafer, for example, silicon is about 3.3×10⁻⁶/K. On the other hand, thecoefficient of linear thermal expansion of a material making up theanisotropically conductive elastomer sheet, for example, silicone rubberis about 2.2×10⁻⁴/K. Accordingly, when a wafer and an anisotropicallyconductive elastomer sheet each having a diameter of 20 cm at 25° C. areheated from 20° C. to 120° C., a change of the wafer in diameter is only0.0066 cm in theory, but a change of the anisotropically conductiveelastomer sheet in diameter amounts to 0.44 cm.

When a great difference is created between the wafer and theanisotropically conductive elastomer sheet in the absolute quantity ofthermal expansion in a plane direction as described above, it isextremely difficult to prevent positional deviation between electrodesto be inspected in the wafer and the conductive parts in theanisotropically conductive elastomer sheet upon the WLBI test even whenthe peripheral edge of the anisotropically conductive elastomer sheet isfixed by a frame plate having an equivalent coefficient of linearthermal expansion to the coefficient of linear thermal expansion of thewafer.

As probe members for the WLBI test, are known those in which ananisotropically conductive elastomer sheet is fixed on to a circuitboard for inspection composed of, for example, a ceramic having anequivalent coefficient of linear thermal expansion to the coefficient oflinear thermal expansion of the wafer (see, for example, Japanese PatentApplication Laid-Open Nos. 231019/1995 and 5666/1996, etc.). In such aprobe member, as means for fixing the anisotropically conductiveelastomer sheet to the circuit board for inspection, a means thatperipheral portions of the anisotropically conductive elastomer sheetare mechanically fixed by, for example, screws or the like, a means thatit is fixed with an adhesive or the like, and the like are considered.

However, in the means that the peripheral portions of theanisotropically conductive elastomer sheet are fixed by the screws orthe like, it is extremely difficult to prevent positional deviationbetween the electrodes to be inspected in the wafer and the conductiveparts in the anisotropically conductive elastomer sheet for the samereasons as the means of fixing to the frame plate as described above.

On the other hand, in the means of fixing with the adhesive, it isnecessary to apply the adhesive only to the insulating part in theanisotropically conductive elastomer sheet in order to surely achieveelectrical connection to the circuit board for inspection. Since theanisotropically conductive elastomer sheet used in the WLBI test issmall in the arrangement pitch of the conductive parts, and a clearancebetween adjacent conductive parts is small, however, it is extremelydifficult in fact to do so. In the means of fixing with the adhesivealso, it is impossible to replace only the anisotropically conductiveelastomer sheet with a new one when the anisotropically conductiveelastomer sheet suffers from trouble, and so it is necessary to replacethe whole probe member including the circuit board for inspection. As aresult, increase in inspection cost is incurred.

DISCLOSURE OF THE INVENTION

The present invention has been made on the basis of the foregoingcircumstances and has as its first object the provision of ananisotropically conductive connector that good conductivity is surelyachieved as to all conductive parts for connection, and insulatingproperty between adjacent conductive parts for connection is surelyachieved even when the pitch of electrodes as objects of connection issmall, and good conductivity is retained over a long period of time evenwhen it is used repeatedly under a high-temperature environment.

A second object of the present invention is to provide ananisotropically conductive connector suitable for use in conductingelectrical inspection of a plurality of integrated circuits formed on awafer in a state of the wafer, by which positioning, and holding andfixing to the wafer can be conducted with ease, good conductivity issurely achieved as to all conductive parts for connection, and moreoverinsulating property between adjacent conductive parts for connection issurely achieved even when the wafer, which is an object of inspection,has a large area of, for example, 8 inches or greater in diameter, andthe pitch of electrodes to be inspected in the integrated circuitsformed is small, and good conductivity is retained over a long period oftime even when it is used repeatedly under a high-temperatureenvironment.

A third object of the present invention is to provide an anisotropicallyconductive connector that a good electrically connected state is stablyretained even with environmental changes such as thermal hysteresis bytemperature change, in addition to the above objects.

A fourth object of the present invention is to provide a conductivepaste composition suitable for forming anisotropically conductive filmsin the above-described anisotropically conductive connectors.

A fifth object of the present invention is to provide a probe member, bywhich positioning, and holding and fixing to a wafer can be conductedwith ease even when the wafer, which is an object of inspection, has alarge area of, for example, 8 inches or greater in diameter, and thepitch of electrodes to be inspected in the integrated circuits formed issmall, and moreover high connection reliability to respective electrodesto be inspected is achieved, and good conductivity is retained over along period of time even when it is used repeatedly under ahigh-temperature environment.

A sixth object of the present invention is to provide a wafer inspectionapparatus and a wafer inspection method for conducting electricalinspection of a plurality of integrated circuits formed on a wafer in astate of the wafer using the above probe member.

According to the present invention, there is thus provided ananisotropically conductive connector comprising an elasticanisotropically conductive film, in which a plurality of conductiveparts for connection containing conductive particles and extending in athickness-wise direction of the film have been formed,

-   -   wherein supposing that the shortest width of each of the        conductive parts for connection is W, and the number average        particle diameter of the conductive particles is Dn, a value of        a ratio W/Dn of the shortest width of the conductive part for        connection to the number average particle diameter of the        conductive particles falls within a range of 3 to 8, and a        coefficient of variation of particle diameter of the conductive        particles is at most 50%.

According to the present invention, there is also provided ananisotropically conductive connector suitable for use in conductingelectrical inspection of each of a plurality of integrated circuitsformed on a wafer in a state of the wafer, which comprises:

-   -   a frame plate, in which a plurality of anisotropically        conductive film-arranging holes each extending in a        thickness-wise direction of the frame plate have been formed        correspondingly to electrode regions, in which electrodes to be        inspected have been arranged, in all or part of the integrated        circuits formed on the wafer, which is an object of inspection,        and a plurality of elastic anisotropically conductive films        arranged in the respective anisotropically conductive        film-arranging holes in this frame plate and each supported by        the peripheral edge about the anisotropically conductive        film-arranging hole,    -   wherein each of the elastic anisotropically conductive films is        composed of a functional part having a plurality of conductive        parts for connection containing conductive particles exhibiting        magnetism at a high density and extending in the thickness-wise        direction of the film, and arranged correspondingly to the        electrodes to be inspected in the integrated circuits formed on        the wafer, which is the object of inspection, and an insulating        part mutually insulating these conductive parts for connection,        and a part to be supported integrally formed at a peripheral        edge of the functional part and fixed to the peripheral edge        about the anisotropically conductive film-arranging hole in the        frame plate, and    -   wherein supposing that the shortest width of each of the        conductive parts for connection is W, and the number average        particle diameter of the conductive particles is Dn, a value of        a ratio W/Dn of the shortest width of the conductive part for        connection to the number average particle diameter of the        conductive particles falls within a range of 3 to 8, and a        coefficient of variation of particle diameter of the conductive        particles is at most 50%.

In the anisotropically conductive connector according to the presentinvention, supposing that the weight average particle diameter of theconductive particles is Dw, a value of a ratio Dw/Dn of the weightaverage particle diameter to the number average particle diameter maypreferably be at most 5.

In the anisotropically conductive connector according to the presentinvention, the number average particle diameter of the conductiveparticles may preferably be 3 to 30 μm.

In the anisotropically conductive connector according to the presentinvention, the conductive particles may preferably be those subjected toa classification treatment by an air classifier.

In the anisotropically conductive connector according to the presentinvention, the conductive particles may preferably be those obtained bycoating surfaces of core particles exhibiting magnetism with ahigh-conductive metal.

In the anisotropically conductive connector according to the presentinvention, the coefficient of linear thermal expansion of the frameplate may preferably be at most 3×10⁻⁵/K.

According to the present invention, there is further provided aconductive paste composition suitable for forming the elasticanisotropically conductive films in the anisotropically conductiveconnectors described above, which comprises curable liquid siliconerubber and conductive particles exhibiting magnetism, wherein supposingthat the shortest width of each of the conductive parts for connectionin the elastic anisotropically conductive film is W, and the numberaverage particle diameter of the conductive particles is Dn, a value ofa ratio W/Dn of the shortest width of the conductive part for connectionto the number average particle diameter of the conductive particlesfalls within a range of 3 to 8, and a coefficient of variation ofparticle diameter of the conductive particles of the conductiveparticles is at most 50%.

According to the present invention, there is still further provided aprobe member suitable for use in conducting electrical inspection ofeach of a plurality of integrated circuits formed on a wafer in a stateof the wafer, which comprises:

-   -   a circuit board for inspection, on the surface of which        inspection electrodes have been formed in accordance with a        pattern corresponding to a pattern of electrodes to be inspected        of the integrated circuits formed on the wafer, which is an        object of inspection, and the above-described anisotropically        conductive connector arranged on the surface of the circuit        board for inspection.

In the probe member according to the present invention, it may bepreferable that the coefficient of linear thermal expansion of the frameplate in the anisotropically conductive connector be at most 3×10⁻⁵/K,and the coefficient of linear thermal expansion of a base materialmaking up the circuit board for inspection be at most 3×10⁻⁵/K.

In the probe member, a sheet-like connector composed of an insulatingsheet and a plurality of electrode structures each extending through ina thickness-wise direction of the insulating sheet and arranged inaccordance with a pattern corresponding to the pattern of the electrodesto be inspected may be arranged on the anisotropically conductiveconnector.

According to the present invention, there is yet still further provideda wafer inspection apparatus for conducting electrical inspection ofeach of a plurality of integrated circuits formed on a wafer in a stateof the wafer, which comprises the probe member described above, whereinelectrical connection to the integrated circuits formed on the wafer,which is an object of inspection, is achieved through the probe member.

According to the present invention, there is yet still further provideda wafer inspection method comprising electrically connecting each of aplurality of integrated circuits formed on a wafer to a tester throughthe probe member described above to perform electrical inspection of theintegrated circuits formed on the wafer.

According to the anisotropically conductive connector of the presentinvention, the number average particle diameter of the conductiveparticles falls within the specific range in the relation to theshortest width of the conductive part for connection, and thecoefficient of variation of particle diameter of the conductiveparticles is at most 50%, so that the conductive particles are thosehaving a particle diameter proper for forming the conductive parts forconnection. Accordingly, the conductive particles are prevented fromremaining in a great amount at portions to become the insulating partsin the molding material layer when a magnetic field is applied to themolding material layer in the formation of the elastic anisotropicallyconductive films, a necessary amount of the conductive particles can begathered in a state accommodated in portions to become the conductiveparts for connection, and moreover the number of the conductiveparticles arranged in the thickness-wise direction can be lessened. As aresult, good conductivity is achieved as to all the conductive parts forconnection formed, and sufficient insulating property is surely achievedbetween adjacent conductive parts for connection. In addition, since thecoating layer having a proper thickness and composed of ahigh-conductive metal can be formed on the conductive particles, it isinhibited to lower the conductivity of the conductive particles at thesurfaces thereof even when the anisotropically conductive connector isused repeatedly under a high-temperature environment, whereby it isprevented to markedly increase the total sum of contact resistance amongthe conductive particles in a conductive path formed in the conductivepart for connection, and so the necessary conductivity is retained overa long period of time.

According to the anisotropically conductive connector for waferinspection, in the frame plate, a plurality of the anisotropicallyconductive film-arranging holes are formed correspondingly to theelectrode regions, in which electrodes to be inspected have been formed,of the integrated circuits in the wafer, which is the object ofinspection, and the elastic anisotropically conductive film is arrangedin each of the anisotropically conductive film-arranging holes, so thatit is hard to be deformed and easy to handle, and the positioning andthe holding and fixing to the wafer can be easily conducted in anelectrically connecting operation to the wafer.

Since the elastic anisotropically conductive film arranged in each ofthe anisotropically conductive film-arranging holes in the frame platemay be small in area, the individual elastic anisotropically conductivefilms are easy to be formed. In addition, since the elasticanisotropically conductive film small in area is little in the absolutequantity of thermal expansion in a plane direction of the elasticanisotropically conductive film even when it is subjected to thermalhysteresis, the thermal expansion of the elastic anisotropicallyconductive film in the plane direction is surely restrained by the frameplate by using a material having a low coefficient of linear thermalexpansion as that for forming the frame plate. Accordingly, a goodelectrically connected state can be stably retained even when the WLBItest is performed on a large-area wafer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating an exemplary anisotropicallyconductive connector according to the present invention.

FIG. 2 is a plan view illustrating, on an enlarged scale, a part of theanisotropically conductive connector shown in FIG. 1.

FIG. 3 is a plan view illustrating, on an enlarged scale, an elasticanisotropically conductive film in the anisotropically conductiveconnector shown in FIG. 1.

FIG. 4 is a cross-sectional view illustrating, on an enlarged scale, theelastic anisotropically conductive film in the anisotropicallyconductive connector shown in FIG. 1.

FIG. 5 is a cross-sectional view illustrating a state that a moldingmaterial has been applied to a mold for molding elastic anisotropicallyconductive films to form molding material layers.

FIG. 6 is a cross-sectional view illustrating, on an enlarged scale, apart of the mold for molding elastic anisotropically conductive films.

FIG. 7 is a cross-sectional view illustrating a state that a frame platehas been arranged through spacers between a top force and a bottom forcein the mold shown in FIG. 5.

FIG. 8 is a cross-sectional view illustrating a state that moldingmaterial layers of the intended form have been formed between the topforce and the bottom force in the mold.

FIG. 9 is a cross-sectional view illustrating, on an enlarged scale, themolding material layer shown in FIG. 8.

FIG. 10 is a cross-sectional view illustrating a state that a magneticfield having a strength distribution has been applied to the moldingmaterial layer shown in FIG. 9 in a thickness-wise direction thereof.

FIG. 11 is a cross-sectional view illustrating the construction of anexemplary wafer inspection apparatus using the anisotropicallyconductive connector according to the present invention.

FIG. 12 is a cross-sectional view illustrating the construction of aprincipal part of an exemplary probe member according to the presentinvention.

FIG. 13 is a cross-sectional view illustrating the construction ofanother exemplary wafer inspection apparatus using the anisotropicallyconductive connector according to the present invention.

FIG. 14 is a plan view illustrating, on an enlarged scale, an elasticanisotropically conductive film in an anisotropically conductiveconnector according to another embodiment of the present invention.

FIG. 15 is a plan view illustrating, on an enlarged scale, an elasticanisotropically conductive film in an anisotropically conductiveconnector according to a further embodiment of the present invention.

FIG. 16 is a top view of a wafer for test used in Examples.

FIG. 17 illustrates a position of a region of electrodes to be inspectedin an integrated circuit formed on the wafer for test shown in FIG. 16.

FIG. 18 illustrates the electrodes to be inspected in the integratedcircuit formed on the wafer for test shown in FIG. 16.

FIG. 19 is a top view of a frame plate produced in Example.

FIG. 20 illustrates, on an enlarged scale, a part of the frame plateshown in FIG. 19.

FIG. 21 illustrates a molding surface of a mold produced in Example onan enlarged scale.

FIG. 22 is a cross-sectional view illustrating a state that a frameplate has been arranged within a mold in a process for producing aconventional anisotropically conductive connector, and moreover amolding material layer has been formed.

DESCRIPTION OF CHARACTERS

-   1 Probe member,-   2 Anisotropically conductive connector,-   3 Pressurizing plate,-   4 Wafer mounting table,-   5 Heater,-   6 Wafer,-   7 Electrodes to be inspected,-   10 Frame plate,-   11 Anisotropically conductive film-arranging holes,-   15 Air circulating holes,-   16 Positioning holes,-   20 Elastic anisotropically conductive films,-   20A Molding material layers,-   21 Functional parts,-   22 Conductive parts for connection,-   23 Insulating part,-   24 Projected parts,-   25 Parts to be supported,-   26 Conductive parts for non-connection,-   27 Projected parts,-   30 Circuit board for inspection,-   31 Inspection electrodes,-   40 Sheet-like connector,-   41 Insulating sheet,-   42 Electrode structures,-   43 Front-surface electrode parts,-   44 Back-surface electrode parts,-   45 Short circuit parts,-   50 Chamber,-   51 Evacuation pipe,-   55 O-rings,-   60 Mold,-   61 Top force,-   62 Base plate,-   63 Ferromagnetic substance layers,-   64 Non-magnetic substance layers,-   64 a Recessed parts,-   65 Bottom force,-   66 Base plate,-   67 Ferromagnetic substance layers,-   68 Non-magnetic substance layers,-   68 a Recessed parts,-   69 a, 69 b Spacers,-   80 Top force,-   81 Ferromagnetic substance layers,-   82 Non-magnetic substance layers,-   85 Bottom force,-   86 Ferromagnetic substance layers,-   87 Non-magnetic substance layers,-   90 Frame plate,-   91 Opening,-   95 Molding material layer-   P Conductive particles.

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiments of the present invention will hereinafter be describedin details.

[Anisotropically Conductive Connector]

FIG. 1 is a plan view illustrating an exemplary anisotropicallyconductive connector according to the present invention, FIG. 2 is aplan view illustrating, on an enlarged scale, a part of theanisotropically conductive connector shown in FIG. 1, FIG. 3 is a planview illustrating, on an enlarged scale, an elastic anisotropicallyconductive film in the anisotropically conductive connector shown inFIG. 1, and FIG. 4 is a cross-sectional view illustrating, on anenlarged scale, the elastic anisotropically conductive film in theanisotropically conductive connector shown in FIG. 1.

The anisotropically conductive connector shown in FIG. 1 is that used inconducting electrical inspection of each of, for example, a plurality ofintegrated circuits formed on a wafer in a state of the wafer and has aframe plate 10 in which a plurality of anisotropically conductivefilm-arranging holes 11 (indicated by broken lines) each extendingthrough in the thickness-wise direction of the frame plate have beenformed as illustrated in FIG. 2. The anisotropically conductivefilm-arranging holes 11 in this frame plate 10 are formed in accordancewith electrode regions, in which electrodes to be inspected have beenformed, in all the integrated circuits formed on the wafer that is anobject of inspection. Elastic anisotropically conductive films 20 havingconductivity in the thickness-wise direction are arranged in therespective anisotropically conductive film-arranging holes 11 in theframe plate 10 in a state they are each supported by the peripheral edgeabout the anisotropically conductive film-arranging hole 11 in the frameplate 10 and in a state independent of adjacent anisotropicallyconductive films 20. In the frame plate 10 of this embodiment are formedair circulating holes 15 for circulating air between the anisotropicallyconductive connector and a member adjacent thereto when a pressurizingmeans of a pressure reducing system is used in a wafer inspectionapparatus, which will be described subsequently. In addition,positioning holes 16 for positioning to the wafer, which is the objectof inspection, and a circuit board for inspection are formed.

Each of the elastic anisotropically conductive films 20 is formed by anelastic polymeric substance and, as illustrated in FIG. 3, has afunctional part 21 composed of a plurality of conductive parts 22 forconnection each extending in the thickness-wise direction (directionperpendicular to the paper in FIG. 3) of the film and an insulating part23 formed around the respective conductive parts 22 for connection andmutually insulating these conductive parts 22 for connection. Thefunctional part 21 is arranged so as to be located in theanisotropically conductive film-arranging hole 11 in the frame plate 10.The conductive parts 22 for connection in the functional part 21 arearranged in accordance with a pattern corresponding to a pattern of theelectrodes to be inspected in the integrated circuit formed on thewafer, which is the object of inspection, and electrically connected tothe electrodes to be inspected in the inspection of the wafer.

At a peripheral edge of the functional part 21, a part 25 to besupported, which has been fixed to and supported by the periphery aboutthe anisotropically conductive film-arranging hole 11 in the frame plate10, is formed integrally and continuously with the functional part 21.More specifically, the part 25 to be supported in this embodiment isshaped in a forked form and fixed and supported in a closely contactedstate so as to grasp the periphery about the anisotropically conductivefilm-arranging hole 11 in the frame plate 10.

In the conductive parts 22 for connection in the functional part 21 ofthe elastic anisotropically conductive film 20, conductive particles Pexhibiting magnetism are contained at a high density in a state orientedso as to align in the thickness-wise direction as illustrated in FIG. 4.On the other hand, the insulating part 23 does not contain theconductive particles P at all or scarcely contain them. In thisembodiment, the part 25 to be supported in the elastic anisotropicallyconductive film 20 contains the conductive particles P.

In the embodiment illustrated, projected parts 24 protruding from othersurfaces than portions, at which the conductive parts 22 for connectionand peripheries thereof are located, are formed at those portions onboth sides of the functional part 21 in the elastic anisotropicallyconductive film 20.

The thickness of the frame plate 10 varies according to the materialthereof, but is preferably 25 to 600 μm, more preferably 40 to 400 μm.

If this thickness is smaller than 25 μm, the strength required upon useof the resulting anisotropically conductive connector is not achieved,and the anisotropically conductive connector tends to be low in thedurability. In addition, such stiffness as the form of the frame plateis retained is not achieved, and the handling property of theanisotropically conductive connector becomes low. If the thicknessexceeds 600 μm on the other hand, the elastic anisotropically conductivefilms 20 formed in the anisotropically conductive film-arranging holes11 become too great in thickness, and it may be difficult in some casesto achieve good conductivity in the conductive parts 22 for connectionand insulating property between adjacent conductive parts 22 forconnection.

The form and size in a plane direction of the anisotropically conductivefilm-arranging holes 11 in the frame plate 10 are designed according tothe size, pitch and pattern of electrodes to be inspected in a waferthat is an object of inspection.

No particular limitation is imposed on a material for forming the frameplate 10 so far as it has such stiffness as the resulting frame plate 10is hard to be deformed, and the form thereof is stably retained. Forexample, various kinds of materials such as metallic materials, ceramicmaterials and resin materials may be used. When the frame plate 10 isformed by, for example, a metallic material, an insulating film may beformed on the surface of the frame plate 10.

Specific examples of the metallic material for forming the frame plate10 include metals such as iron, copper, nickel, chromium, cobalt,magnesium, manganese, molybdenum, indium, lead, palladium, titanium,tungsten, aluminum, gold, platinum and silver, and alloys or alloysteels composed of a combination of at least two of these metals.

Specific examples of the resin material forming the frame plate 10include liquid crystal polymers and polyimide resins.

The frame plate 10 may preferably exhibit magnetism at least at theperipheral portion about the anisotropically conductive film-arrangingholes 11 thereof, i.e., a portion supporting the elastic anisotropicallyconductive film 20 in that the conductive particles P can be caused tobe contained with ease in the part 25 to be supported in the elasticanisotropically conductive film 20 by a process which will be describedsubsequently. Specifically, this portion may preferably have asaturation magnetization of at least 0.1 Wb/m². In particular, the wholeframe plate 10 may preferably be formed by a magnetic substance in thatthe frame plate 10 is easy to be produced.

Specific examples of the magnetic substance forming such a frame plate10 include iron, nickel, cobalt, alloys of these magnetic metals, andalloys or alloy steels of these magnetic metals with any other metal.

When the anisotropically conductive connector is used in the WLBI test,it is preferable to use a material having a coefficient of linearthermal expansion of at most 3×10⁻⁵/K, more preferably −1×10⁻⁷ to1×10⁻⁵/K, particularly preferably 1×10⁻⁶ to 8×10⁻⁶/K as a material forforming the frame plate 10.

Specific examples of such a material include invar alloys such as invar,Elinvar alloys such as Elinvar, and alloys or alloy steels of magneticmetals, such as superinvar, covar and 42 alloy.

The overall thickness (thickness of the conductive part 22 forconnection in the illustrated embodiment) of the elastic anisotropicallyconductive film 20 is preferably 50 to 2,000 μm, more preferably 70 to1,000 μm, particularly preferably 80 to 500 μm. When this thickness is50 μm or greater, an elastic anisotropically conductive film 20 havingsufficient strength is provided with certainty. When this thickness is2,000 μm or smaller on the other hand, conductive parts 22 forconnection having necessary conductive properties are provided withcertainty.

The projected height of each projected part 24 is preferably at least10% in total of the thickness in the projected part 24, more preferablyat least 20%. Projected parts 24 having such a projected height areformed, whereby the conductive parts 22 for connection are sufficientlycompressed by small pressurizing force, so that good conductivity issurely achieved.

The projected height of the projected part 24 is preferably at most100%, more preferably at most 70% of the shortest width or diameter ofthe projected part 24. Projected parts 24 having such a projected heightare formed, whereby the projected parts are not buckled when they arepressurized, so that the prescribed conductivity is surely achieved.

The thickness (thickness of one of the forked portions in theillustrated embodiment) of the part 25 to be supported is preferably 5to 250 μm, more preferably 10 to 150 μm, particularly preferably 15 to100 μm.

It is not essential to form the part 25 to be supported in the forkedform, and it may be fixed to only one surface of the frame plate 10.

The elastic polymeric substance forming the elastic anisotropicallyconductive films 20 is preferably a heat-resistant polymeric substancehaving a crosslinked structure. Various materials may be used as curablepolymeric substance-forming materials usable for obtaining such acrosslinked polymeric substance. However, liquid silicone rubber ispreferred.

The liquid silicone rubber may be any of addition type and condensationtype. However, the addition type liquid silicone rubber is preferred.This addition type liquid silicone rubber is that cured by a reaction ofa vinyl group with an Si—H bond and includes a one-pack type(one-component type) composed of polysiloxane having both vinyl groupand Si—H bond and a two-pack type (two-component type) composed ofpolysiloxane having a vinyl group and polysiloxane having an Si—H bond.In the present invention, addition type liquid silicone rubber of thetwo-pack type is preferably used.

As the addition type liquid silicone rubber, is used that having aviscosity of preferably 100 to 1,250 Pa·s, more preferably 150 to 800Pa·s, particularly preferably 250 to 500 Pa·s at 23° C. If thisviscosity is lower than 100 Pa·s, precipitation of the conductiveparticles in such addition type liquid silicone rubber is easy to occurin a molding material for obtaining the elastic anisotropicallyconductive films 20, which will be described subsequently, so that goodstorage stability is not obtained. In addition, the conductive particlesare not oriented so as to align in the thickness-wise direction of themolding material layer when a parallel magnetic field is applied to themolding material layer, so that it may be difficult in some cases toform chains of the conductive particles in an even state. If thisviscosity exceeds 1,250 Pa·s on the other hand, the viscosity of theresulting molding material becomes too high, so that it may be difficultin some cases to form the molding material layer in the mold. Inaddition, the conductive particles are not sufficiently moved even whena parallel magnetic field is applied to the molding material layer.Therefore, it may be difficult in some cases to orient the conductiveparticles so as to align in the thickness-wise direction.

The viscosity of such addition type liquid silicone rubber can bemeasured by means of a Brookfield type viscometer.

When the elastic anisotropically conductive films 20 are formed by acured product (hereinafter referred to as “cured silicone rubber”) ofthe liquid silicone rubber, the cured silicone rubber preferably has acompression set of at most 10%, more preferably at most 8%, still morepreferably at most 6% at 150° C. If the compression set exceeds 10%,chains of the conductive particles P in the conductive part 22 forconnection is disordered when the resulting anisotropically conductiveconnector is used repeatedly under a high-temperature environment. As aresult, it is difficult to retain the necessary conductivity.

In the present invention, the compression set of the cured siliconerubber can be measured by a method in accordance with JIS K 6249.

The cured silicone rubber forming the elastic anisotropically conductivefilms 20 preferably has a durometer A hardness of 10 to 60, morepreferably 15 to 60, particularly preferably 20 to 60 at 23° C. If thedurometer A hardness is lower than 10, the insulating part 23 mutuallyinsulating the conductive parts 22 for connection is easilyover-distorted when pressurized, and it may be difficult in some casesto retain the necessary insulating property between the conductive parts22 for connection. If the durometer A hardness exceeds 60 on the otherhand, pressurizing force of a considerably heavy load is required forgiving proper distortion to the conductive parts 22 for connection, sothat, for example, a wafer, which is an object of inspection, tends tocause great deformation or breakage.

In the present invention, the durometer A hardness of the cured siliconerubber can be measured by a method in accordance with JIS K 6249.

Further, the cured silicone rubber for forming the elasticanisotropically conductive films 20 preferably has tear strength of atleast 8 kN/m, more preferably at least 10 kN/m, still more preferably atleast 15 kN/m, particularly preferably at least 20 kN/m at 23° C. If thetear strength is lower than 8 kN/m, the resulting elasticanisotropically conductive films 20 tend to deteriorate durability whenthey are distorted in excess.

In the present invention, the tear strength of the cured silicone rubbercan be measured by a method in accordance with JIS K 6249.

As the addition type liquid silicone rubber having such properties, maybe used that marketed as liquid silicone rubber “KE2000” series or“KE1950” series from Shin-Etsu Chemical Co., Ltd.

In the present invention, a proper curing catalyst may be used forcuring the addition type liquid silicone rubber. As such a curingcatalyst, may be used a platinum-containing catalyst. Specific examplesthereof include publicly known catalysts such as platinic chloride andsalts thereof, platinum-unsaturated group-containing siloxane complexes,vinylsiloxane-platinum complexes,platinum-1,3-divinyltetramethyldisiloxane complexes, complexes oftriorganophosphine or phosphine and platinum, acetyl acetate platinumchelates, and cyclic diene-platinum complexes.

The amount of the curing catalyst used is suitably selected in view ofthe kind of the curing catalyst and other curing treatment conditions.However, it is generally 3 to 15 parts by weight per 100 parts by weightof the addition type liquid silicone rubber.

In order to improve the thixotropic property of the addition type liquidsilicone rubber, adjust the viscosity, improve the dispersion stabilityof the conductive particles or provide a base material having highstrength, a general inorganic filler such as silica powder, colloidalsilica, aerogel silica or alumina may be contained in the addition typeliquid silicone rubber as needed.

No particular limitation is imposed on the amount of such an inorganicfiller used. However, the use in a too large amount is not preferredbecause the orientation of the conductive particles P by a magneticfield cannot be sufficiently achieved.

Supposing that the number average particle diameter of the conductiveparticles is Dn, and the shortest width of each of the conductive parts22 for connection is W, those that a value of a ratio W/Dn (hereinafterreferred to as “ration W/Dn” merely) of the shortest width of theconductive part for connection to the number average particle diameterof the conductive particles falls within a range of 3 to 8, preferablyfrom 4 to 7 are used as the conductive particles P contained in theconductive parts 22 for connection and the parts 25 to be supported ineach of the elastic anisotropically conductive films 20.

In the present invention, the average particle diameter of particlesmeans a value measured by a laser diffraction scattering method.

If the value of the ratio W/Dn is smaller than 3, it is difficult tosurely achieve the necessary insulating property between adjacentconductive parts 22 for connection. If the ratio W/Dn exceeds 8 on theother hand, the total sum of contact resistance between the conductiveparticles forming one conductive path increases because the particlediameter of the conductive particles P is too small, so that it isdifficult to surely form conductive parts 22 for connection having highconductivity. In addition, since a great amount of the conductiveparticles P remain in the insulating part 23, it is difficult to surelyachieve the necessary insulating property between adjacent conductiveparts 22 for connection. Further, a coating layer having a properthickness cannot be formed on the conductive particles P, so that theconductivity of the conductive particles at the surfaces thereof isdeteriorated when the resulting anisotropically conductive connector isused repeatedly under a high-temperature environment. As a result, it isdifficult to retain the necessary conductivity.

Further, as the conductive particles P, are used those that acoefficient of variation of particle diameter thereof is at most 50%,preferably at most 35%.

In the present invention, the coefficient of variation of particlediameter is a value determined in accordance with the expression:(σ/Dn)×100, wherein a is a standard deviation value of the particlediameter.

If the coefficient of variation of particle diameter of the conductiveparticles P exceeds 50%, it is difficult to surely achieve the necessaryinsulating property between adjacent conductive parts 22 for connection.

Supposing that the weight average particle diameter of the conductiveparticles is Dw, those that a value of a ratio Dw/Dn (hereinafterreferred to as “ration Dw/Dn” merely) of the weight average particlediameter to the number average particle diameter is at most 5 arepreferably used as the conductive particles P, with those that the valueof the ratio Dw/Dn is at most 3 being more preferred. By using suchconductive particles, the necessary insulating property between adjacentconductive parts 22 for connection can be more surely achieved.

The number average particle diameter of the conductive particles P ispreferably 3 to 30 μm, more preferably 6 to 15 μm.

If this number average particle diameter is smaller than 3 μm, it isdifficult to surely form conductive parts 22 for connection having highconductivity. It is also difficult to surely achieve the necessaryinsulating property between adjacent conductive parts 22 for connection.It is further difficult to retain the necessary conductivity when theresulting anisotropically conductive connector is used repeatedly undera high-temperature environment. If this number average particle diameterexceeds 30 μm on the other hand, it is impossible to design the value ofthe ratio W/Dn within the above-described range when the shortest widthof each of the conductive parts 22 for connection to be formed is small.

No particular limitation is imposed on the form of the conductiveparticles P. However, they are preferably in the form of a sphere orstar, or a mass of secondary particles obtained by agglomerating theseparticles in that these particles can be easily dispersed in thepolymeric substance-forming material.

As the conductive particles P, are preferably used those obtained bycoating the surfaces of core particles (hereinafter also referred to as“magnetic core particles”) exhibiting magnetism with a high-conductivemetal.

The term “high-conductive metal” as used herein means a metal having anelectric conductivity of at least 5×10⁶ Ω⁻¹m⁻¹ at 0° C.

As a material for forming the magnetic core particles, may be used iron,nickel, cobalt, a material obtained by coating such a metal with copperor a resin, or the like. Those having a saturation magnetization of atleast 0.1 Wb/m² may be preferably used. The saturation magnetizationthereof is more preferably at least 0.3 Wb/m², particularly preferablyat least 0.5 Wb/m². As specific examples thereof, may be mentioned iron,nickel, cobalt and alloys thereof. Among these, nickel is preferred.

When this saturation magnetization is at least 0.1 Wb/m², the conductiveparticles P can be easily moved in the molding material layers forforming the elastic anisotropically conductive films 20 by a process,which will be described subsequently, whereby the conductive particles Pcan be surely moved to portions to become conductive parts forconnection in the respective molding material layers to form chains ofthe conductive particles P.

As the high-conductive metal coating the magnetic core particles, may beused gold, silver, rhodium, platinum, chromium or the like. Among these,gold is preferably used in that it is chemically stable and has a highelectric conductivity.

In order to obtain conductive parts 22 for connection having highconductivity, those that a proportion [(mass of high-conductivemetal/mass of core particles)×100] of the high-conductive metal to thecore particles is at least 15% by mass, preferably 25 to 35% by mass arepreferably used as the conductive particles P.

The content of water in the conductive particles P is preferably at most5%, more preferably at most 3%, still more preferably at most 2%,particularly preferably at most 1%. By using the conductive particles Psatisfying such conditions, bubbling in the molding material layer canbe prevented or inhibited upon the curing treatment of the moldingmaterial layer in a production process, which will be describedsubsequently.

Such conductive particles P may be obtained in accordance with, forexample, the following process.

Particles are first formed from a ferromagnetic material in accordancewith a method known per se in the art, or commercially availableparticles of a ferromagnetic substance are provided. The particles aresubjected to a classification treatment as needed.

In the present invention, the classification treatment of the particlescan be conducted by means of, for example, a classifier such as an airclassifier or sonic classifier.

Specific conditions for the classification treatment are suitably presetaccording to the intended number average particle diameter of themagnetic core particles, the kind of the classifier, and the like.

Surfaces of the magnetic core particles are then treated with an acidand further washed with, for example, purified water, thereby removingimpurities such as dirt, foreign matter and oxidized films present onthe surfaces of the magnetic core particles. Thereafter, the surfaces ofthe magnetic core particles are coated with a high-conductive metal,thereby obtaining conductive particles exhibiting magnetism.

As the acid used for treating the surfaces of the magnetic coreparticles, may be mentioned hydrochloric acid or the like.

As a method for coating the surfaces of the magnetic core particles withthe high-conductive metal, may be used electroless plating, displacementplating or the like. However, the method is not limited to thesemethods.

A process for producing the conductive particles by the electrolessplating or displacement plating will be described. The magnetic coreparticles subjected to the acid treatment and washing treatment arefirst added to a plating solution to prepare a slurry, and electrolessplating or displacement plating on the magnetic core particles isconducted while stirring the slurry. The particles in the slurry arethen separated from the plating solution. Thereafter, the particlesseparated are subjected to a washing treatment with, for example,purified water, thereby obtaining conductive particles with the surfacesof the magnetic core particles coated with the high-conductive metal.

Alternatively, primer plating may be conducted on the surfaces of themagnetic core particles to form a primer plating layer, and a platinglayer formed of the high-conductive metal may be then formed on thesurface of the primer plating layer. No particular limitation is imposedon the process for forming the primer plating layer and the platinglayer formed thereon. However, it is preferable to form the primerplating layer on the surfaces of the magnetic core particles by theelectroless plating and then form the plating layer formed of thehigh-conductive metal on the surface of the primer plating layer by thedisplacement plating.

No particular limitation is imposed on the plating solution used in theelectroless plating or displacement plating, and various kinds ofcommercially available plating solutions may be used.

The conductive particles obtained in such a manner are subjected to aclassification treatment for the purpose of providing particles havingthe above-described particle diameter and particle diameterdistribution.

As a classifier used for conducting the classification treatment of theconductive particles, may be used those exemplified as the classifierused in the classification treatment of the magnetic core particles.However, at least the air classifier is preferably used. By subjectingthe conductive particles to the classification treatment by the airclassifier, conductive particles having the above-described particlediameter and particle diameter distribution can be surely obtained.

The conductive particles P may be treated with a coupling agent such asa silane coupling agent as needed. By treating the surfaces of theconductive particles P with the coupling agent, the adhesion property ofthe conductive particles P to the elastic polymeric substance isenhanced. As a result, the resulting anisotropically conductive films 20become high in durability upon repeated use.

The amount of the coupling agent used is suitably selected within limitsnot affecting the conductivity of the conductive particles P. However,it is preferably such an amount that a coating rate (proportion of anarea coated with the coupling agent to the surface area of theconductive core particles) of the coupling agent on the surfaces of theconductive particles P amounts to at least 5%, more preferably 7 to100%, still more preferably 10 to 100%, particularly preferably 20 to100%.

The proportion of the conductive particles P contained in the conductiveparts 22 for connection in the functional part 21 is preferably 10 to60%, more preferably 15 to 50% in terms of volume fraction. If thisproportion is lower than 10%, it may be impossible in some cases toobtain conductive parts 22 for connection sufficiently low in electricresistance value. If this proportion exceeds 60% on the other hand, theresulting conductive parts 22 for connection are liable to be brittle,so that elasticity required of the conductive parts 22 for connectionmay not be achieved in some cases.

The proportion of the conductive particles P contained in the parts 25to be supported varies according to the content of the conductiveparticles in the molding material for forming the elasticanisotropically conductive films 20. However, it is preferablyequivalent to or more than the proportion of the conductive particlescontained in the molding material in that the conductive particles P aresurely prevented from being contained in excess in the conductive parts22 for connection located most outside among the conductive parts 22 forconnection in the elastic anisotropically conductive film 20. It is alsopreferably at most 30% in terms of volume fraction in that parts 25 tobe supported having sufficient strength are provided.

The anisotropically conductive connector described above may beproduced, for example, in the following manner.

A frame plate 10 composed of a magnetic metal, in which anisotropicallyconductive film-arranging holes 11 have been formed correspondingly to apattern of electrode regions, in which electrodes to be inspected havebeen formed, of integrated circuits in a wafer that is an object ofinspection is first produced. As a method for forming theanisotropically conductive film-arranging holes 11 in the frame plate10, may be used, for example, an etching method or the like.

A conductive paste composition with conductive particles exhibitingmagnetism dispersed in addition type liquid silicone rubber is thenprepared. As illustrated in FIG. 5, a mold 60 for molding elasticanisotropically conductive films is provided, and the conductive pastecomposition as a molding material for elastic anisotropically conductivefilms is applied to the respective molding surfaces of a top force 61and a bottom force 65 in the mold 60 in accordance with a necessarypattern, namely, an arrangement pattern of elastic anisotropicallyconductive films to be formed, thereby forming molding material layers20A.

Here, the mold 60 will be described specifically. This mold 60 is soconstructed that the top force 61 and the bottom force 65 making a pairtherewith are arranged so as to be opposed to each other.

In the top force 61, ferromagnetic substance layers 63 are formed inaccordance with a pattern antipodal to an arrangement pattern of theconductive parts 22 for connection in each of the elasticanisotropically conductive films 20 to be molded on the lower surface ofa base plate 62, and non-magnetic substance layers 64 are formed atother portions than the ferromagnetic substance layers 63 asillustrated, on an enlarged scale, in FIG. 6. The molding surface isformed by these ferromagnetic substance layers 63 and non-magneticsubstance layers 64. Recessed parts 64 a are formed in the moldingsurface of the top force 61 corresponding to the projected parts 24 inthe elastic anisotropically conductive films 20 to be molded.

In the bottom force 65 on the other hand, ferromagnetic substance layers67 are formed in accordance with the same pattern as the arrangementpattern of the conductive parts 22 for connection in the elasticanisotropically conductive films 20 to be molded on the upper surface ofa base plate 66, and non-magnetic substance layers 68 are formed atother portions than the ferromagnetic substance layers 67. The moldingsurface is formed by these ferromagnetic substance layers 67 andnon-magnetic substance layers 68. Recessed parts 68 a are formed in themolding surface of the bottom force 65 corresponding to the projectedparts 24 in the elastic anisotropically conductive films 20 to bemolded.

The respective base plates 62 and 66 in the top force 61 and bottomforce 65 are preferably formed by a ferromagnetic substance. Specificexamples of such a ferromagnetic substance include ferromagnetic metalssuch as iron, iron-nickel alloys, iron-cobalt alloys, nickel and cobalt.The base plates 62, 66 preferably have a thickness of 0.1 to 50 mm, andare preferably smooth at surfaces thereof and subjected to a chemicaldegreasing treatment or mechanical polishing treatment.

As a material for forming the ferromagnetic substance layers 63, 67 inboth top force 61 and bottom force 65, may be used a ferromagnetic metalsuch as iron, iron-nickel alloy, iron-cobalt alloy, nickel or cobalt.The ferromagnetic substance layers 63, 67 preferably have a thickness ofat least 10 μm. When this thickness is at least 10 μm, a magnetic fieldhaving a sufficient intensity distribution can be applied to the moldingmaterial layers 20A. As a result, the conductive particles can begathered at a high density at portions to become conductive parts 22 forconnection in the molding material layers 20A, and so conductive parts22 for connection having good conductivity can be provided.

As a material for forming the non-magnetic substance layers 64, 68 inboth top force 61 and bottom force 65, may be used a non-magnetic metalsuch as copper, a polymeric substance having heat resistance, or thelike. However, a polymeric substance cured by radiation may preferablybe used in that the non-magnetic substance layers 64, 68 can be easilyformed by a technique of photolithography. As a material thereof, may beused, for example, a photoresist such as an acrylic type dry filmresist, epoxy type liquid resist or polyimide type liquid resist.

As a method for coating the molding surfaces of the top force 61 andbottom force 65 with the molding material, may preferably be used ascreen printing method. According to such a method, the molding materialcan be easily applied according to a necessary pattern, and a properamount of the molding material can be applied.

As illustrated in FIG. 7, the frame plate 10 is then arranged inalignment on the molding surface of the bottom force 65, on which themolding material layers 20A have been formed, through a spacer 69 a, andon the frame plate 10, the top force 61, on which the molding materiallayers 20A have been formed, is arranged in alignment through a spacer69 b. These top and bottom forces are superimposed on each other,whereby molding material layers 20A of the intended form (form of theelastic anisotropically conductive films 20 to be formed) are formedbetween the top force 61 and the bottom force 65 as illustrated in FIG.8. In each of these molding material layers 20A, the conductiveparticles P are contained in a state dispersed throughout in the moldingmaterial layer 20A as illustrated in FIG. 9.

As described above, the spacers 69 a and 69 b are arranged between theframe plate 10, and the bottom force 65 and the top force 61,respectively, whereby the elastic anisotropically conductive films ofthe intended form can be formed, and adjacent elastic anisotropicallyconductive films are prevented from being connected to each other, sothat a great number of anisotropically conductive films independent ofone another can be formed with certainty.

A pair of, for example, electromagnets are then arranged on the uppersurface of the base plate 62 in the top force 61 and the lower surfaceof the base plate 66 in the bottom force 65, and the electromagnets areoperated, whereby a magnetic field having higher intensity at portionsbetween the ferromagnetic substance layers 63 of the top force 61 andtheir corresponding ferromagnetic substance layers 67 of the bottomforce 65 than surrounding regions thereof is formed because the topforce 61 and the bottom force 65 have the ferromagnetic substance layers63 and 67, respectively. As a result, in the molding material layers20A, the conductive particles P dispersed in the molding material layers20A are gathered at portions to become the conductive parts 22 forconnection, which are located between the ferromagnetic substance layers63 of the respective top force 61 and their corresponding ferromagneticsubstance layers 67 of the bottom force 65, and oriented so as to alignin the thickness-wise direction of the molding material layers asillustrated in FIG. 10. In the above-described process, the frame plate10 is composed of the magnetic metal, so that a magnetic field havinghigher intensity at portions between the frame plate 10, and therespective top force 61 and the bottom force 65 than vicinities thereofis formed. As a result, the conductive particles P existing above andbelow the frame plate 10 in the molding material layers 20A are notgathered between the ferromagnetic substance layers 63 of the top force61 and the ferromagnetic substance layers 67 of the bottom force 65, butremain retained above and below the frame plate 10.

In this state, the molding material layers 20A are subjected to a curingtreatment, whereby the elastic anisotropically conductive films 20 eachcomposed of a functional part 21, in which a plurality of conductiveparts 22 for connection containing the conductive particles P in theelastic polymeric substance in a state oriented so as to align in thethickness-wise direction are arranged in a state mutually insulated byan insulating part 23 composed of the elastic polymeric substance, inwhich the conductive particles P are not present at all or scarcelypresent, and a part 25 to be supported, which is continuously andintegrally formed at a peripheral edge of the functional part 21 and inwhich the conductive particles P are contained in the elastic polymericsubstance, are formed in a state that the part 25 to be supported hasbeen fixed to the periphery about each anisotropically conductivefilm-arranging hole 11 of the frame plate 10, thereby producing ananisotropically conductive connector.

In the above-described process, the intensity of the external magneticfield applied to the portions to become the conductive parts 22 forconnection and the portions to become the parts 25 to be supported inthe molding material layers 20A is preferably an intensity that itamounts to 0.1 to 2.5 T on the average.

The curing treatment of the molding material layers 20A is suitablyselected according to the material used. However, the treatment isgenerally conducted by a heat treatment. When the curing treatment ofthe molding material layers 20A is conducted by heating, it is onlynecessary to provide a heater in an electromagnet. Specific heatingtemperature and heating time are suitably selected in view of the kindsof the polymeric substance-forming material forming the molding materiallayer 20A, and the like, the time required for movement of theconductive particles P, and the like.

According to the anisotropically conductive connector described above,the number average particle diameter of the conductive particles P fallswithin the specific range in the relation to the shortest width of theconductive part 22 for connection, and the coefficient of variation ofparticle diameter is at most 50%, so that the conductive particles P arethose having a particle diameter proper for forming the conductive parts22 for connection. Accordingly, the conductive particles P are preventedfrom remaining in a great amount at portions to become the insulatingparts 23 in the molding material layer 20A when a magnetic field isapplied to the molding material layer 20A in the formation of theelastic anisotropically conductive films 20, a necessary amount of theconductive particles P can be gathered in a state accommodated inportions to become the conductive parts 22 for connection, and moreoverthe number of the conductive particles P arranged in the thickness-wisedirection can be lessened. As a result, good conductivity is achieved asto all the conductive parts 22 for connection formed, and sufficientinsulating property is surely achieved between adjacent conductive parts22 for connection. In addition, since the coating layer having a properthickness and formed of a high-conductive metal can be formed on theconductive particles P, it is inhibited to lower the conductivity of theconductive particles P at the surfaces thereof even when theanisotropically conductive connector is used repeatedly under ahigh-temperature environment, whereby it is prevented to markedlyincrease the total sum of contact resistance among the conductiveparticles P in a conductive path formed in the conductive part 22 forconnection, and so the necessary conductivity can be retained over along period of time.

Since the part 25 to be supported is formed at the peripheral edge ofthe functional part 21 having the conductive parts 22 for connection ineach of the elastic anisotropically conductive films 20, and this part25 to be supported is fixed to the periphery about the anisotropicallyconductive film-arranging hole 11 in the frame plate 10, theanisotropically conductive connector is hard to be deformed and easy tohandle, so that the positioning and the holding and fixing to a wafer,which is an object of inspection, can be easily conducted in anelectrically connecting operation to the wafer.

Since the respective anisotropically conductive film-arranging holes 11in the frame plate 10 are formed correspondingly to the electroderegions, in which electrodes to be inspected have been formed, ofintegrated circuits in a wafer, which is an object of inspection, andthe elastic anisotropically conductive film 20 arranged in each of theanisotropically conductive film-arranging holes 11 may be small in area,the individual elastic anisotropically conductive films 20 are easy tobe formed. In addition, since the elastic anisotropically conductivefilm 20 small in area is little in the absolute quantity of thermalexpansion in a plane direction of the elastic anisotropically conductivefilm 20 even when it is subjected to thermal hysteresis, the thermalexpansion of the elastic anisotropically conductive film 20 in the planedirection is surely restrained by the frame plate by using a materialhaving a low coefficient of linear thermal expansion as that for formingthe frame plate 10. Accordingly, a good electrically connected state canbe stably retained even when the WLBI test is performed on a large-areawafer.

Since the above-described anisotropically conductive connector isobtained by subjecting the molding material layers 20A to the curingtreatment in a state that the conductive particles P have been retainedin the portions to become the parts 25 to be supported in the moldingmaterial layers 20A by, for example, applying a magnetic field to thoseportions in the formation of the elastic anisotropically conductivefilms 20, the conductive particles P existing in the portions to becomethe parts 25 to be supported in the molding material layers 20A, i.e.,portions located above and below the peripheries about theanisotropically conductive film-arranging holes 11 in the frame plate 10are not gathered at the portions to become the conductive parts 22 forconnection. As a result, the conductive particles P are prevented frombeing contained in excess in the conductive parts 22 for connection,which are located most outside among the conductive parts 22 forconnection in the resulting elastic anisotropically conductive films 20.Accordingly, there is no need of reducing the content of the conductiveparticles P in the molding material layers 20A, so that goodconductivity is achieved with certainty in all the conductive parts 22for connection in the elastic anisotropically conductive films 20, andmoreover insulating property between adjacent conductive parts 22 forconnection can be achieved with certainty.

Since the positioning holes 16 are formed in the frame plate 10,positioning to the wafer, which is the object of inspection, or thecircuit board for inspection can be easily conducted.

Since the air circulating holes 15 are formed in the frame plate 10, airexisting between the anisotropically conductive connector and thecircuit board for inspection is discharged through the air circulatingholes 15 in the frame plate 10 at the time the pressure within a chamberis reduced when that by the pressure reducing system is utilized as themeans for pressing the probe member in a wafer inspection apparatus,which will be described subsequently, whereby the anisotropicallyconductive connector can be surely brought into close contact with thecircuit board for inspection, so that the necessary electricalconnection can be achieved with certainty.

[Wafer Inspection Apparatus]

FIG. 11 is a cross-sectional view schematically illustrating theconstruction of an exemplary wafer inspection apparatus making use ofthe anisotropically conductive connector according to the presentinvention. This wafer inspection apparatus serves to perform electricalinspection of each of a plurality of integrated circuits formed on awafer in a state of the wafer.

The wafer inspection apparatus shown in FIG. 11 has a probe member 1 forconducting electrical connection of each of electrodes 7 to be inspectedof a wafer 6, which is an object of inspection, to a tester. As alsoillustrated on an enlarged scale in FIG. 12, the probe member 1 has acircuit board 30 for inspection, on the front surface (lower surface inFIG. 11) of which a plurality of inspection electrodes 31 have beenformed in accordance with a pattern corresponding to a pattern of theelectrodes 7 to be inspected of the wafer 6 that is the object ofinspection. On the front surface of the circuit board 30 for inspectionis provided the anisotropically conductive connector 2 of theconstruction illustrated in FIGS. 1 to 4 in such a manner that theconductive parts 22 for connection in the elastic anisotropicallyconductive films 20 of the connector are opposed to and brought intocontact with the inspection electrodes 31 of the circuit board 30 forinspection, respectively. On the front surface (lower surface in FIG.11) of the anisotropically conductive connector 2 is provided asheet-like connector 40, in which a plurality of electrode structures 42have been arranged in an insulating sheet 41 in accordance with thepattern corresponding to the pattern of the electrodes 7 to be inspectedof the wafer 6 that is the object of inspection, in such a manner thatthe electrode structures 42 are opposed to and brought into contact withthe conductive parts 22 for connection in the elastic anisotropicallyconductive films 20 of the anisotropically conductive connector 2,respectively.

On the back surface (upper surface in the figure) of the circuit board30 for inspection in the probe member 1 is provided a pressurizing plate3 for pressurizing the probe member 1 downward. A wafer mounting table4, on which the wafer 6 that is the object of inspection is mounted, isprovided below the probe member 1. A heater 5 is connected to each ofthe pressurizing plate 3 and the wafer mounting table 4.

As a base material for making up the circuit board 30 for inspection,may be used any of conventionally known various base materials. Specificexamples thereof include composite resin materials such as glassfiber-reinforced epoxy resins, glass fiber-reinforced phenol resins,glass fiber-reinforced polyimide resins and glass fiber-reinforcedbismaleimidotriazine resins, and ceramic materials such as glass,silicon dioxide and alumina.

When a wafer inspection apparatus for performing the WLBI test isconstructed, a material having a coefficient of linear thermal expansionof at most 3×10⁻⁵/K, more preferably 1×10⁻⁷ to 1×10⁻⁵/K, particularlypreferably 1×10⁻⁶ to 6×10⁻⁶/K is preferably used.

Specific examples of such a base material include Pyrex (registeredtrademark) glass, quartz glass, alumina, beryllia, silicon carbide,aluminum nitride and boron nitride.

The sheet-like connector 40 in the probe member 1 will be describedspecifically. This sheet-like connector 40 has a flexible insulatingsheet 41, and in this insulating sheet 41, a plurality of electrodestructures 42 extending in the thickness-wise direction of theinsulating sheet 41 and composed of a metal are arranged in a stateseparated from each other in a plane direction of the insulating sheet41 in accordance with the pattern corresponding to the pattern of theelectrodes 7 to be inspected of the wafer 6 that is the object ofinspection.

Each of the electrode structures 42 is formed by integrally connecting aprojected front-surface electrode part 43 exposed to the front surface(lower surface in the figure) of the insulating sheet 41 and aplate-like back-surface electrode part 44 exposed to the back surface ofthe insulating sheet 41 to each other by a short circuit part 45extending through in the thickness-wise direction of the insulatingsheet 41.

No particular limitation is imposed on the insulating sheet 41 so far asit has insulating property and is flexible. For example, a resin sheetformed of a polyamide resin, liquid crystal polymer, polyester,fluororesin or the like, or a sheet obtained by impregnating a clothwoven by fibers with any of the above-described resins may be used.

No particular limitation is also imposed on the thickness of theinsulating sheet 41 so far as such an insulating sheet 41 is flexible.However, it is preferably 10 to 50 μm, more preferably 10 to 25 μm.

As a metal for forming the electrode structures 42, may be used nickel,copper, gold, silver, palladium, iron or the like. The electrodestructures 42 may be any of those formed of a single metal, those formedof an alloy of at least two metals and those obtained by laminating atleast two metals as a whole.

On the surfaces of the front-surface electrode part 43 and back-surfaceelectrode part 44 in the electrode structure 42, a film of a metal,chemically stable and having high conductivity, such as gold, silver orpalladium is preferably formed in that oxidation of the electrode partsis prevented, and electrode parts small in contact resistance areobtained.

The projected height of the front-surface electrode part 43 in theelectrode structure 42 is preferably 15 to 50 μm, more preferably 15 to30 μm in that stable electrical connection to the electrode 7 to beinspected of the wafer 6 can be achieved. The diameter of thefront-surface electrode part 43 is preset according to the size andpitch of the electrodes to be inspected of the wafer 6 and is, forexample, 30 to 80 μm, preferably 30 to 50 μm.

The diameter of the back-surface electrode part 44 in the electrodestructure 42 may be greater than the diameter of the short circuit part45 and smaller than the arrangement pitch of the electrode structures 42and is preferably great as much as possible, whereby stable electricalconnection to the conductive part 22 for connection in the elasticanisotropically conductive film 20 of the anisotropically conductiveconnector 2 can also be achieved with certainty. The thickness of theback-surface electrode part 44 is preferably 20 to 50 μm, morepreferably 35 to 50 μm in that the strength is sufficiently high, andexcellent repetitive durability is achieved.

The diameter of the short circuit part 45 in the electrode structure 42is preferably 30 to 80 μm, more preferably 30 to 50 μm in thatsufficiently high strength is achieved.

The sheet-like connector 40 can be produced, for example, in thefollowing manner.

More specifically, a laminate material obtained by laminating a metallayer on an insulating sheet 41 is provided, and a plurality ofthrough-holes extending through in the thickness-wise direction of theinsulating sheet 41 are formed in the insulating sheet 41 of thelaminate material in accordance with a pattern corresponding to apattern of electrode structures 42 to be formed by laser machining, dryetch machining or the like. This laminate material is then subjected tophotolithography and plating treatment, whereby short circuit parts 45integrally connected to the metal layer are formed in the through-holesin the insulating sheet 41, and at the same time, projectedfront-surface electrode parts 43 integrally connected to the respectiveshort circuit parts 45 are formed on the front surface of the insulatingsheet 41. Thereafter, the metal layer of the laminate material issubjected to a photo-etching treatment to remove a part thereof, therebyforming back-surface electrode parts 44 to form the electrode structures42, whereby the sheet-like connector 40 is provided.

In such an electrical inspection apparatus, a wafer 6, which is anobject of inspection, is mounted on the wafer mounting table 4, and theprobe member 1 is then pressurized downward by the pressurizing plate 3,whereby the respective front-surface electrode parts 43 in the electrodestructures 42 of the sheet-like connector 40 thereof are brought intocontact with their corresponding electrodes 7 to be inspected of thewafer 6, and moreover the respective electrodes 7 to be inspected of thewafer 6 are pressurized by the front-surface electrodes parts 43. Inthis state, each of the conductive parts 22 for connection in theelastic anisotropically conductive films 20 of the anisotropicallyconductive connector 2 are respectively held and pressurized by theinspection electrodes 31 of the circuit board 30 for inspection and thefront-surface electrode parts 43 of the electrode structures 42 of thesheet-like connector 40 and compressed in the thickness-wise directionof the elastic anisotropically conductive films 20, whereby conductivepaths are formed in the respective conductive parts 22 for connection inthe thickness-wise direction thereof. As a result, electrical connectionbetween the electrodes 7 to be inspected of the wafer 6 and theinspection electrodes 31 of the circuit board 30 for inspection isachieved. Thereafter, the wafer 6 is heated to a prescribed temperaturethrough the wafer mounting table 4 and the pressurizing plate 3 by theheater 5. In this state, necessary electrical inspection is performed oneach of a plurality of integrated circuits in the wafer 6.

According to such a wafer inspection apparatus, electrical connection tothe electrodes 7 to be inspected of the wafer 6, which is the object ofinspection, is achieved through the probe member 1 having theabove-described anisotropically conductive connector 2. Therefore,positioning, and holding and fixing to the wafer can be conducted withease even when the pitch of the electrodes 7 to be inspected is small.In addition, high connection reliability to the respective electrodes tobe inspected is achieved, and moreover the necessary electricalinspection can be stably performed over a long period of time even whenthe apparatus is used repeatedly under a high-temperature environmentbecause the conductive parts 22 for connection of the elasticanisotropically conductive films 20 in the anisotropically conductiveconnector 2 have good conductivity, and insulating property betweenadjacent conductive parts 22 for connection is sufficiently retained.

Since each of the elastic anisotropically conductive films 20 in theanisotropically conductive connector 2 is small in its own area, and theabsolute quantity of thermal expansion in a plane direction thereof ofthe elastic anisotropically conductive film 20 is little even when it issubjected to thermal hysteresis, the thermal expansion of the elasticanisotropically conductive film 20 in the plane direction thereof issurely restrained by the frame plate by using a material having a lowcoefficient of linear thermal expansion as that for forming the frameplate 10. Accordingly, a good electrically connected state can be stablyretained even when the WLBI test is performed on a large-area wafer.

FIG. 13 is a cross-sectional view schematically illustrating theconstruction of another exemplary wafer inspection apparatus making useof the anisotropically conductive connector according to the presentinvention.

This wafer inspection apparatus has a box-type chamber 50 opened at thetop thereof, in which a wafer 6 that is an object of inspection isreceived. An evacuation pipe 51 for evacuating air within the chamber 50is provided in a sidewall of this chamber 50, and an evacuator (notillustrated) such as, for example, a vacuum pump, is connected to theevacuation pipe 51.

A probe member 1 of the same construction as the probe member 1 in thewafer inspection apparatus shown in FIG. 11 is arranged on the chamber50 so as to air-tightly close the opening of the chamber 50. Morespecifically, an elastic O-ring 55 is arranged in close contact on anupper end surface of the sidewall in the chamber 50, and the probemember 1 is arranged in a state that the anisotropically conductiveconnector 2 and sheet-like connector 40 thereof have been housed in thechamber 50, and the periphery of the circuit board 30 for inspectionthereof has been brought into close contact with the O-ring. Further,the circuit board 30 for inspection is held in a state pressurizeddownward by a pressurizing plate 3 provided on the back surface (uppersurface in the figure) thereof.

A heater 5 is connected to the chamber 50 and the pressurizing plate 3.

In such a wafer inspection apparatus, the evacuator connected to theevacuation pipe 51 of the chamber 50 is driven, whereby the pressurewithin the chamber 50 is reduced to, for example, 1,000 Pa or lower. Asa result, the probe member 1 is pressurized downward by the atmosphericpressure, whereby the O-ring 55 is elastically deformed, and so theprobe member 1 is moved downward. As a result, electrodes 7 to beinspected of the wafer 6 are respectively pressurized by theircorresponding front-surface electrode parts 43 in electrode structures42 of the sheet-like connector 40. In this state, the conductive parts22 for connection in the elastic anisotropically conductive films 20 ofthe anisotropically conductive connector 2 are respectively held andpressurized by the inspection electrodes 31 of the circuit board 30 forinspection and the front-surface electrode parts 43 in the electrodestructures 42 of the sheet-like connector 40 and compressed in thethickness-wise direction of the elastic anisotropically conductive films20, whereby conductive paths are formed in the respective conductiveparts 22 for connection in the thickness-wise direction thereof. As aresult, electrical connection between the electrodes 7 to be inspectedof the wafer 6 and the inspection electrodes 31 of the circuit board 30for inspection is achieved. Thereafter, the wafer 6 is heated to aprescribed temperature through the chamber 50 and the pressurizing plate3 by the heater 5. In this state, necessary electrical inspection isperformed on each of a plurality of integrated circuits in the wafer 6.

According to such a wafer inspection apparatus, the same effects asthose about the wafer inspection apparatus shown in FIG. 11 are broughtabout. In addition, the whole inspection apparatus can be miniaturizedbecause any large-sized pressurizing mechanism is not required, andmoreover the whole wafer 6, which is the object of inspection, can bepressed by even force even when the wafer 6 has a large area of, forexample, 8 inches or greater in diameter. In addition, since the aircirculating holes 15 are formed in the frame plate 10 in theanisotropically conductive connector 2, air existing between theanisotropically conductive connector 2 and the circuit board 30 forinspection is discharged through the air circulating holes 15 of theframe plate 10 in the anisotropically conductive connector 2 at the timethe pressure within the chamber 50 is reduced, whereby theanisotropically conductive connector 2 can be surely brought into closecontact with the circuit board 30 for inspection, so that the necessaryelectrical connection can be achieved with certainty.

Other Embodiments

The present invention is not limited to the above-described embodiments,and such various changes or modifications as described below may beadded thereto.

(1) In the anisotropically conductive connector, conductive parts fornon-connection that are not to be electrically connected to anyelectrode to be inspected in a wafer may be formed in the elasticanisotropically conductive films 20 in addition to the conductive parts22 for connection. An anisotropically conductive connector havingelastic anisotropically conductive films, in which the conductive partsfor non-connection have been formed, will hereinafter be described.

FIG. 14 is a plan view illustrating, on an enlarged scale, an elasticanisotropically conductive film in an anisotropically conductiveconnector according to another embodiment of the present invention. Inthe elastic anisotropically conductive film 20 of this anisotropicallyconductive connector, a plurality of conductive parts 22 for connectionthat are electrically connected to electrodes to be inspected in awafer, which is an object of inspection, and extend in thethickness-wise direction (direction perpendicular to the paper in FIG.14) of the film are arranged in the functional part 21 thereof, so as toalign in 2 rows in accordance with a pattern corresponding to a patternof the electrodes to be inspected. These conductive parts 22 forconnection respectively contain conductive particles exhibitingmagnetism at a high density in a state oriented so as to align in thethickness-wise direction and are mutually insulated by an insulatingpart 23, in which the conductive particles are not contained at all orscarcely contained.

Conductive parts 26 for non-connection that are not to be electricallyconnected to any electrode to be inspected in the wafer, which is theobject of inspection, and extend in the thickness-wise direction areformed between the conductive parts 22 for connection located mostoutside in a direction that the conductive parts 22 for connection arearranged and the frame plate 10. The conductive parts 26 fornon-connection contain the conductive particles exhibiting magnetism ata high density in a state oriented so as to align in the thickness-wisedirection and are mutually insulated from the conductive parts 22 forconnection by an insulating part 23, in which the conductive particlesare not contained at all or scarcely contained.

In the embodiment illustrated, projected parts 24 and projected parts 27protruding from other surfaces than portions, at which the conductiveparts 22 for connection and peripheries thereof are located, andportions, at which the conductive parts 26 for non-connection andperipheries thereof are located, are formed at those portions on bothsides of the functional part 21 in the elastic anisotropicallyconductive film 20.

At the peripheral edge of the functional part 21, a part 25 to besupported that is fixed to and supported by the peripheral edge aboutthe anisotropically conductive film-arranging hole 11 in the frame plate10 is integrally and continuously formed with the functional part 21,and the conductive particles are contained in this part 25 to besupported.

Other constitutions are basically the same as those in theanisotropically conductive connector shown in FIGS. 1 to 4.

FIG. 15 is a plan view illustrating, on an enlarged scale, an elasticanisotropically conductive film in an anisotropically conductiveconnector according to a further embodiment of the present invention. Inthe elastic anisotropically conductive film 20 of this anisotropicallyconductive connector, a plurality of conductive parts 22 for connectionthat are electrically connected to electrodes to be inspected in awafer, which is an object of inspection, and extend in thethickness-wise direction (direction perpendicular to the paper in FIG.15) of the film are arranged so as to align in accordance with a patterncorresponding to a pattern of the electrodes to be inspected. Theseconductive parts 22 for connection respectively contain conductiveparticles exhibiting magnetism at a high density in a state oriented soas to align in the thickness-wise direction and are mutually insulatedby an insulating part 23, in which the conductive particles are notcontained at all or scarcely contained.

Among these conductive parts 22 for connection, 2 conductive parts 22for connection, which are located at the center and adjoin each other,are arranged at a clearance greater than a clearance between otheradjacent conductive parts 22 for connection. A conductive part 26 fornon-connection that is not to be electrically connected to any electrodeto be inspected in the wafer, which is the object for inspection, andextends in the thickness-wise direction is formed between the 2conductive parts 22 for connection, which are located at the center andadjoin each other. This conductive part 26 for non-connection containsthe conductive particles exhibiting magnetism at a high density in astate oriented so as to align in the thickness-wise direction and ismutually insulated from the conductive parts 22 for connection by aninsulating part 23, in which the conductive particles are not containedat all or scarcely contained.

In the embodiment illustrated, projected parts 24 and projected parts 27protruding from other surfaces than portions, at which the conductiveparts 22 for connection and peripheries thereof are located, and aportion, at which the conductive part 26 for non-connection and aperiphery thereof are located, are formed at those portions on bothsides of the functional part 21 in the elastic anisotropicallyconductive film 20.

At the peripheral edge of the functional part 21, a part 25 to besupported that is fixed to and supported by the peripheral edge aboutthe anisotropically conductive film-arranging hole 11 in the frame plate10 is integrally and continuously formed with the functional part 21,and the conductive particles are contained in this part 25 to besupported.

Other specific constitutions are basically the same as those in theanisotropically conductive connector shown in FIGS. 1 to 4.

The anisotropically conductive connector shown in FIG. 14 and theanisotropically conductive connector shown in FIG. 15 can be produced ina similar manner to the process for producing the anisotropicallyconductive connector shown in FIGS. 1 to 4 by using a mold composed of atop force and a bottom force, on which ferromagnetic substance layershave been respectively formed in accordance with a pattern correspondingto an arrangement pattern of the conductive parts 22 for connection andconductive parts 26 for non-connection in the elastic anisotropicallyconductive films 20 to be formed, and non-magnetic substance layers havebeen formed at portions other than the ferromagnetic substance layers,in place of the mold shown in FIG. 6.

More specifically, according to such a mold, a pair of, for example,electromagnets are arranged on an upper surface of a base plate in thetop force and a lower surface of a base plate in the bottom force, andthe electromagnets are operated, whereby in molding material layersformed between the top force and the bottom force, conductive particlesdispersed in portions to become the functional parts 21 in the moldingmaterial layers are gathered at portions to become the conductive parts22 for connection and the portions to become the conductive parts 26 fornon-connection, and oriented so as to align in the thickness-wisedirection of the molding material layers. On the other hand, theconductive particles located above and below the frame plate 10 in themolding material layers remain retained above and below the frame plate10.

In this state, the molding material layers are subjected to a curingtreatment, whereby the elastic anisotropically conductive films 20 eachcomposed of the functional part 21, in which a plurality of theconductive parts 22 for connection and conductive parts 26 fornon-connection containing the conductive particles in the elasticpolymeric substance in a state oriented so as to align in thethickness-wise direction are arranged in a state mutually insulated bythe insulating part 23 composed of the elastic polymeric substance, inwhich the conductive particles are not present at all or scarcelypresent, and the part 25 to be supported, which is continuously andintegrally formed at a peripheral edge of the functional part 21 and inwhich the conductive particles are contained in the elastic polymericsubstance, are formed in a state that the part 25 to be supported hasbeen fixed to the periphery about each anisotropically conductivefilm-arranging hole 11 of the frame plate 10, thereby producing theanisotropically conductive connector.

The conductive parts 26 for non-connection in the anisotropicallyconductive connector shown in FIG. 14 are each obtained by applying amagnetic field to portions to become the conductive parts 26 fornon-connection in the molding material layer upon the formation of theelastic anisotropically conductive film 20 to gather the conductiveparticles existing between the portions to become the conductive parts22 for connection, located most outside in the molding material layer,and the frame plate 10 at the portions to become the conductive partsfor non-connection, and subjecting the molding material layer to acuring treatment in this state. Thus, upon the formation of the elasticanisotropically conductive film 20 the conductive particles areprevented from being gathered in excess in the portions to become theconductive parts 22 for connection, which are located most outside inthe molding material layer. Accordingly, even when the respectiveelastic anisotropically conductive films 20 to be formed each havecomparatively many conductive parts 22 for connection, it is surelyprevented to contain an excessive amount of the conductive particles inthe conductive parts 22 for connection located most outside in theelastic anisotropically conductive film 20.

The conductive parts 26 for non-connection in the anisotropicallyconductive connector shown in FIG. 15 are each obtained by, upon theformation of the elastic anisotropically conductive film 20, applying amagnetic field to the portion to become the conductive part 26 fornon-connection in the molding material layer to gather the conductiveparticles existing between the 2 adjacent portions to become theconductive parts 22 for connection arranged at a greater clearance inthe molding material layer, at the portion to become the conductive part26 for non-connection, and subjecting the molding material layer to acuring treatment in this state. Thus, upon the formation of the elasticanisotropically conductive film 20, the conductive particles areprevented from being gathered in excess at the 2 adjacent portions tobecome the conductive parts 22 for connection arranged at a greaterclearance in the molding material layer. Accordingly, even when therespective elastic anisotropically conductive films 20 to be formed haveat least 2 conductive parts 22 for connection arranged at a greaterclearance, it is surely prevented to contain an excessive amount of theconductive particles in these conductive parts 22 for connection.

(2) In the anisotropically conductive connector, the projected parts 24in the elastic anisotropically conductive films 20 are not essential,and one or both surfaces may be flat, or a recessed portion may beformed.

(3) A metal layer may be formed on the surfaces of the conductive parts22 for connection in the elastic anisotropically conductive films 20.

(4) When a non-magnetic substance is used as a base material of theframe plate 10 in the production of the anisotropically conductiveconnector, a means of plating peripheries about the anisotropicallyconductive film-arranging holes in the frame plate 10 with a magneticsubstance or coating them with a magnetic paint to apply a magneticfield thereto, or a means of forming ferromagnetic substance layers inthe mold 60 corresponding to the parts 25 to be supported of the elasticanisotropically conductive films 20 to apply a magnetic field theretomay be utilized as a method for applying the magnetic field to portionsto become the parts 25 to be supported in the molding material layers20A.

(5) The use of the spacer is not essential in the formation of themolding material layers, and spaces for forming the elasticanisotropically conductive films may be surely retained between the topforce and bottom force, and the frame plate by any other means.

(6) In the probe member, the sheet-like connector 40 is not essential,and the elastic anisotropically conductive films 20 in theanisotropically conductive connector 2 may be brought into contact witha wafer, which is an object of inspection, to achieve electricalconnection.

(7) In the anisotropically conductive connector according to the presentinvention, the anisotropically conductive film-arranging holes in theframe plate thereof may be formed correspondingly to electrode regions,in which electrodes to be inspected have been arranged, in part ofintegrated circuits formed on a wafer, which is an object of inspection,and the elastic anisotropically conductive film may be arranged in eachof these anisotropically conductive film-arranging holes.

According to such an anisotropically conductive connector, a wafer canbe divided into two or more areas to collectively perform the probe teston integrated circuits formed in each of the divided areas.

More specifically, it is not essential to collectively performinspection on all the integrated circuits formed on the wafer in thewafer inspection process using the anisotropically conductive connectoraccording to the present invention or the probe member according to thepresent invention.

In the burn-in test, inspection time required of each of integratedcircuits is as long as several hours, and so high time efficiency can beachieved when the inspection is conducted collectively on all integratedcircuits formed on a wafer. In the probe test on the other hand,inspection time required of each of integrated circuits is as short asseveral minutes, and so sufficiently high time efficiency can beachieved even when a wafer is divided into 2 or more areas, and theprobe test is conducted collectively on integrated circuits formed ineach of the divided areas.

As described above, according to the method that electrical inspectionis conducted every area divided as to integrated circuits formed on awafer, when the electrical inspection is conducted as to integratedcircuits formed at a high degree of integration on a wafer having adiameter of 8 inches or 12 inches, the numbers of inspection electrodesand wires of the circuit board for inspection used can be reducedcompared with the method that the inspection is conducted collectivelyon all the integrated circuits, whereby the production cost of theinspection apparatus can be reduced.

Since the anisotropically conductive connector according to the presentinvention or the probe member according to the present invention is highin durability in repeated use, the frequency to replace theanisotropically conductive connector suffers from trouble with a new onebecomes low when it is used in the method that the electrical inspectionis conducted every area divided as to integrated circuits formed on thewafer, so that inspection cost can be reduced.

(8) The anisotropically conductive connector according to the presentinvention or the probe member according to the present invention mayalso be used in inspection of a wafer, on which integrated circuitshaving projected electrodes (bumps) formed of gold, solder or the likehave been formed, in addition to the inspection of a wafer, on whichintegrated circuits having flat electrodes formed of aluminum have beenformed.

Since the electrode formed of gold, solder or the like is hard to forman oxidized film on its surface compared with the electrode composed ofaluminum, there is no need of pressurizing such an electrode under aload required for breaking through the oxidized film in the inspectionof the wafer, on which the integrated circuit having such projectedelectrodes have been formed, so that the inspection can be performed ina state that the conductive parts for connection of an anisotropicallyconductive connector have been brought into direct contact with theelectrodes to be inspected without using any sheet-like connector.

When inspection of a wafer is conducted in a state that conductive partsfor connection of an anisotropically conductive connector have beenbrought into direct contact with the projected electrodes, which areelectrodes to be inspected, the conductive parts for connection undergoabrasion or permanent compressive deformation by being pressurized bythe projected electrodes when the anisotropically conductive connectoris used repeatedly. As a result, increase in electric resistance andconnection failure to the electrodes to be inspected occur in theconductive parts for connection, so that it has been necessary toreplace the anisotropically conductive connector by a new one at a highfrequency.

According to the anisotropically conductive connector according to thepresent invention or the probe member according to the presentinvention, however, the necessary conductivity is retained over a longperiod of time even when the wafer, which is an object of inspection, isa wafer having a diameter of 8 inches or 12 inches, on which integratedcircuits have been formed at a high degree of integration, since theanisotropically conductive connector or probe member is high indurability in repeated use, whereby the frequency to replace theanisotropically conductive connector with a new one becomes low, and sothe inspection cost can be reduced.

The present invention will hereinafter be described specifically by thefollowing examples. However, the present invention is not limited tothese examples.

[Preparation of Conductive Particles]

Into a treating vessel of a powder plating apparatus, were poured 100 gof particles composed of nickel (saturation magnetization: 0.6 Wb/m²)having a number average particle diameter of 10 μm, and 2 L of 0.32Nhydrochloric acid were added. The resultant mixture was stirred toobtain a slurry containing core particles. This slurry was stirred atordinary temperature for 30 minutes, thereby conducting an acidtreatment for the core particles. Thereafter, the slurry thus treatedwas left at rest for 1 minute to precipitate the core particles, and asupernatant was removed.

To the core particles subjected to the acid treatment, were added 2 L ofpurified water, and the mixture was stirred at ordinary temperature for2 minutes. The mixture was then left at rest for 1 minute to precipitatethe magnetic core particles, and a supernatant was removed. This processwas conducted repeatedly further twice, thereby conducting a washingtreatment for the core particles.

To the core particles subjected to the acid treatment and washingtreatment, were added 2 L of a plating solution of gold containing goldin a proportion of 20 g/L. The temperature of the treating vessel wasraised to 90° C., and the contents were stirred, thereby preparing aslurry. While stirring the slurry in this state, the magnetic coreparticles were subjected to displacement plating with gold. Thereafter,the slurry was left at rest while allowing it to cool, therebyprecipitating particles, and a supernatant was removed to prepareconductive particles with the surfaces of the core particles, which iscomposed of nickel, coated with gold.

To the conductive particles thus obtained, were added 2 L of purifiedwater, and the mixture was stirred at ordinary temperature for 2minutes. Thereafter, the mixture was left at rest for 1 minute toprecipitate the conductive particles, and a supernatant was removed.This process was conducted repeatedly further twice, and 2 L of purifiedwater heated to 90° C. was added to the particles, and the mixture wasstirred. The resultant slurry was filtered through filter paper tocollect the conductive particles. The conductive particles thus obtainedwere subjected to a drying treatment by a dryer preset at 90° C.

An air classifier “Turboclassifier TC-15N” (manufactured by NisshinEngineering Co., Ltd.) was used to subject 200 g of the conductiveparticles to a classification treatment under conditions of a specificgravity of 8.9, an air flow of 2.5 m³/min, a rotor speed of 1,600 rpm, aclassification point of 25 μm and a feed rate of the conductiveparticles of 16 g/min, thereby collecting 180 g of conductive particles.Further, 180 g of the conductive particles were subjected to anotherclassification treatment under conditions of a specific gravity of 8.9,an air flow of 25 m³/min, a rotor speed of 3,000 rpm, a classificationpoint of 10 μm and a feed rate of the conductive particles of 14 g/min,thereby collecting 150 g of conductive particles.

The thus-obtained conductive particles were such that the number averageparticle diameter is 8.7 μm, the weight average particle diameter is 9.9μm, a value of a ratio Dw/Dn is 1.1, the standard deviation of particlediameter is 2.0, the coefficient of variation of particle diameter is23%, and the proportion of gold to the core particles is 30% by mass.The conductive particles will be referred to as “Conductive Particles(1)”.

Thirteen kinds of conductive particles were also prepared in the samemanner as in the preparation of Conductive Particles (1) except that thenumber average particle diameter of the magnetic core particles used,conditions for the plating and classification conditions of the airclassifier were suitably changed. These conductive particles will bereferred to as “Conductive Particles (2)” to “Conductive Particles(14)”. The number average particle diameters, weight average particlediameters, values of the ratio Dw/Dn, standard deviations of particlediameter, coefficients of variation of particle diameter and proportionsof gold to the magnetic core particles of these conductive particles areshown in the following Table TABLE 1 Number Weight Proportion averageaverage Coefficient of gold to particle particle of core diameterdiameter Standard variation particles (μm) (μm) Dw/Dn deviation (%)(mass %) Conductive (1) 8.7 9.9 1.1 2.0 23 30 particles (2) 8.3 9.9 1.22.3 28 28 (3) 7.7 9.1 1.2 2.0 26 27 (4) 8.6 10.4 1.2 2.5 29 29 (5) 14.820.6 1.4 6.2 42 23 (6) 19.2 25.1 1.3 7.2 38 15 (7) 5.3 12.3 2.3 7.6 14318 (8) 4.2 15.6 3.7 11.9 283 17 (9) 3.2 16.1 5.1 13.6 429 10 (10)  9.620.4 2.1 7.9 81 5 (11)  19.2 24.9 1.3 6.9 36 8 (12)  5.7 15.8 2.8 7.8137 12 (13)  5.6 14.5 2.6 7.3 130 13 (14)  9.3 23.2 2.5 11.1 119 6[Production of Wafer for Test]

As illustrated in FIG. 16, 596 square integrated circuits L in total,which each had dimensions of 6.5 mm×6.5 mm, were formed on a wafer 6made of silicon (coefficient of linear thermal expansion: 3.3×10⁻⁶/K)and having a diameter of 8 inches. Each of the integrated circuits Lformed on the wafer 6 has a region A of electrodes to be inspected atits center as illustrated in FIG. 17. In the region A of the electrodesto be inspected, as illustrated in FIG. 18, 26 rectangular electrodes 7to be inspected each having dimensions of 200 μm in a vertical direction(upper and lower direction in FIG. 18) and 60 μm in a lateral direction(left and right direction in FIG. 18) are arranged at a pitch of 100 μmin 2 lines (the number of electrodes 7 to be inspected in a line: 13) inthe lateral direction. A clearance between electrodes 7 to be inspectedadjacent in the vertical direction is 450 μm. Every two electrodes amongthe 26 electrodes 7 to be inspected are electrically connected to eachother. The total number of the electrodes 7 to be inspected in the wholewafer is 15,496. This wafer will hereinafter be referred to as “Wafer(1) for test”.

On the other hand, 596 integrated circuits L in total, which had thesame construction as in the above-described Wafer (1) for test exceptthat all electrodes to be inspected were electrically insulated from oneanother, were formed on a wafer. This wafer will hereinafter be referredto as “Wafer (2) for test”.

EXAMPLE 1

(1) Frame Plate:

A frame plate having a diameter of 8 inches and 596 anisotropicallyconductive film-arranging holes formed correspondingly to the respectiveregions of the electrodes to be inspected in Wafer W for test describedabove was produced under the following conditions in accordance with theconstruction shown in FIGS. 19 and 20.

A material of this frame plate is covar (saturation magnetization: 1.4Wb/m²; coefficient of linear thermal expansion: 5×10⁻⁶/K), and thethickness thereof is 60 μm.

The anisotropically conductive film-arranging holes 11 each havedimensions of 1,540 μm in a lateral direction (left and right directionin FIGS. 19 and 20) and 600 μm in a vertical direction (upper and lowerdirection in FIGS. 19 and 20).

A circular air circulating hole 15 is formed at a central positionbetween anisotropically conductive film-arranging holes 11 adjacent inthe vertical direction, and the diameter thereof is 1,000 μm.

(2) Spacer:

Two spacers for molding elastic anisotropically conductive films, whichrespectively have a plurality of through-holes formed correspondingly tothe regions of the electrodes to be inspected in Wafer W for test, wereproduced under the following conditions.

A material of these spacers is stainless steel (SUS304), and thethickness thereof is 20 μm.

The through-hole corresponding to each region of the electrodes to beinspected has dimensions of 2,200 μm in the lateral direction and 1,400μm in the vertical direction.

(3) Mold:

A mold for molding elastic anisotropically conductive films was producedunder the following conditions in accordance with the construction shownin FIGS. 6 and 21.

A top force 61 and a bottom force 65 in this mold respectively have baseplates 62 and 66 made of iron and each having a thickness of 6 mm. Onthe base plate, 62, 66 ferromagnetic substance layers 63 (67) forforming conductive parts for connection and ferromagnetic substancelayers 63 a (67 a) for forming conductive parts for non-connection,which are made of nickel, are arranged in accordance with a patterncorresponding to a pattern of the electrodes to be inspected in Wafer Wfor test. More specifically, the dimensions of each of the ferromagneticsubstance layers 63 (67) for forming conductive parts for connection are50 μm (lateral direction)×200 μm (vertical direction)×100 μm(thickness), and 26 ferromagnetic substance layers 63 (67) are arrangedat a pitch of 100 μm in 2 lines (the number of ferromagnetic substancelayers 63 (67) in a line: 13; clearance between ferromagnetic substancelayers 63 (67) adjacent in the vertical direction: 450 μm) in thelateral direction. The ferromagnetic substance layers 63 a (67 a) forforming conductive parts for non-connection are arranged outside theferromagnetic substance layers 63 (67) located most outside in adirection that the ferromagnetic substance layers 63 (67) are arranged.The dimensions of each of the ferromagnetic substance layers 63 a (67 a)are 80 μm (lateral direction)×300 μm (vertical direction)×100 μm(thickness).

Corresponding to the regions of the electrodes to be inspected in WaferW for test, are formed 596 regions in total, in each of which 26ferromagnetic substance layers 63 (67) for forming conductive parts forconnection and 2 ferromagnetic substance layers 63 a (67 a) for formingconductive parts for non-connection have been formed. In the whole baseplate, are formed 15,496 ferromagnetic substance layers 63 (67) forforming conductive parts for connection and 1,192 ferromagneticsubstance layers 63 a (67 a) for forming conductive parts fornon-connection.

Non-magnetic substance layers 64 (68) are formed by subjecting dry filmresists to a curing treatment. The dimensions of each of recessed parts64 a (68 a), at which the ferromagnetic substance layer 63 (67) forforming the conductive part for connection is located, are 60 μm(lateral direction)×210 μm (vertical direction)×25 μm (depth), thedimensions of each of recessed parts 64 b (68 b), at which theferromagnetic substance layer 63 a (67 a) for forming the conductivepart for non-connection is located, are 90 μm (lateral direction)×260 μm(vertical direction)×25 μm (depth), and the thickness of other portionsthan the recessed parts is 125 μm (the thickness of the recessed parts:100 μm).

(4) Elastic Anisotropically Conductive Film:

The above-described frame plate, spacers and mold were used to formelastic anisotropically conductive films in the frame plate in thefollowing manner.

To 100 parts by weight of addition type liquid silicone rubber wereadded and mixed 30 parts by weight of Conductive Particles (1).Thereafter, the resultant mixture was subjected to a defoaming treatmentby pressure reduction, thereby preparing a conductive paste composition.

In the above process, that of a two-pack type that the viscosity ofLiquid A is 250 Pa·s, the viscosity of Liquid B is 250 Pa·s, thecompression set of a cured product thereof at 150° C. is 5%, thedurometer A hardness of the cured product is 32, and the tear strengthof the cured product is 25 kN/m was used as the addition type liquidsilicone rubber.

The properties of the addition type liquid silicone rubber weredetermined in the following manner.

(i) Viscosity of Addition Type Liquid Silicone Rubber:

A viscosity at 23±2° C. was measured by a Brookfield viscometer.

(ii) Compression Set of Cured Silicone Rubber:

Solution A and Solution B in addition type liquid silicone rubber of thetwo-pack type were stirred and mixed in proportions that their amountsbecome equal. After this mixture was then poured into a mold andsubjected to a defoaming treatment by pressure reduction, a curingtreatment was conducted under conditions of 120° C. for 30 minutes,thereby producing a columnar body having a thickness of 12.7 mm and adiameter of 29 mm and composed of cured silicone rubber. The columnarbody was post-cured under conditions of 200° C. for 4 hours. Thecolumnar body thus obtained was used as a specimen to measure itscompression set at 150±2° C. in accordance with JIS K 6249.

(iii) Tear Strength of Cured Silicone Rubber:

A curing treatment and post-curing of addition type liquid siliconerubber were conducted under the same conditions as in the item (ii),thereby producing a sheet having a thickness of 2.5 mm. A crescent typespecimen was prepared by punching from this sheet to measure its tearstrength at 23±2° C. in accordance with JIS K 6249.

(iv) Durometer A Hardness:

Five sheets produced in the same manner as in the item (iii) werestacked on one another, and the resultant laminate was used as aspecimen to measure its durometer A hardness at 23±2° C. in accordancewith JIS K 6249.

The conductive paste composition prepared as a molding material forelastic anisotropically conductive films was applied to the surfaces ofthe top force and bottom force of the mold by screen printing, therebyforming molding material layers in accordance with a pattern of theelastic anisotropically conductive films to be formed, and the frameplate was superimposed in alignment on the molding surface of the bottomforce through the spacer on the side of the bottom force. Further, thetop force was superimposed in alignment on the frame plate through thespacer on the side of the top force.

The molding material layers formed between the top force and the bottomforce were subjected to a curing treatment under conditions of 100° C.for 1 hour while applying a magnetic field of 2 T to portions locatedbetween the corresponding ferromagnetic substance layers in thethickness-wise direction by electromagnets, thereby forming an elasticanisotropically conductive film in each of the anisotropicallyconductive film-arranging holes of the frame plate, thus producing ananisotropically conductive connector. This anisotropically conductiveconnector will hereinafter be referred to as “Anisotropically ConductiveConnector C1”.

The elastic anisotropically conductive films thus obtained will bedescribed specifically. Each of the elastic anisotropically conductivefilms has dimensions of 2,200 μm in the lateral direction and 1,400 μmin the vertical direction. In a functional part in each of the elasticanisotropically conductive films, 26 conductive parts for connection arearranged at a pitch of 100 μm in 2 lines (the number of conductive partsfor connection in a line: 13; clearance between conductive parts forconnection adjacent in the vertical direction: 450 μm) in the lateraldirection. The dimensions of each of the conductive parts for connectionare 50 μm in the lateral direction, 200 μm in the vertical direction and150 μm in thickness. The value of a ratio W/Dn of the shortest width W(50 μm) of the conductive part for connection to the number averageparticle diameter Dn of Conductive Particles (1) is 5.8, and thethickness of the insulating part in the functional part is 100 μm.Conductive parts for non-connection are arranged between the conductiveparts for connection located most outside in the lateral direction andthe frame plate. The dimensions of each of the conductive parts fornon-connection are 80 μm in the lateral direction, 300 μm in thevertical direction and 150 μm in thickness. The thickness (thickness ofone of the forked portions) of the part to be supported in each of theelastic anisotropically conductive films is 20 μm.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C1 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

(5) Circuit Board for Inspection:

Alumina ceramic (coefficient of linear thermal expansion: 4.8×10⁻⁶/K)was used as a base material to produce a circuit board for inspection,in which inspection electrodes had been formed in accordance with apattern corresponding to the pattern of the electrodes to be inspectedin Wafer W for test. This circuit board for inspection is rectangularwith dimensions of 30 cm×30 cm as a whole. The inspection electrodesthereof each have dimensions of 60 μm in the lateral direction and 200μm in the vertical direction. This circuit board for inspection willhereinafter be referred to as “Inspection Circuit Board T”.

(6) Sheet-Like Connector:

A laminate material obtained by laminating a copper layer having athickness of 15 μm on one surface of an insulating sheet formed ofpolyimide and having a thickness of 20 μm was provided, and 15,496through-holes each extending through in the thickness-wise direction ofthe insulating sheet and having a diameter of 30 μm were formed in theinsulating sheet of the laminate material in accordance with a patterncorresponding to the pattern of electrodes to be inspected in Wafer Wfor test by subjecting the insulating sheet to laser machining. Thislaminate material was then subjected to photolithography and platingtreatment with nickel, whereby short circuit parts integrally connectedto the copper layer were formed in the through-holes in the insulatingsheet, and at the same time, projected front-surface electrode partsintegrally connected to the respective short circuit parts were formedon the front surface of the insulating sheet. The diameter of each ofthe front-surface electrode parts was 40 μm, and the height from thesurface of the insulating sheet was 20 μm. Thereafter, the copper layerof the laminate material was subjected to a photo-etching treatment toremove a part thereof, thereby forming rectangular back-surfaceelectrode parts each having dimensions of 70 μm×210 μm. Further, thefront-surface electrode parts and back-surface electrode parts weresubjected to a plating treatment with gold, thereby forming electrodestructures, thus producing a sheet-like connector. This sheet-likeconnector will hereinafter be referred to as “Sheet-like Connector M”.

(7) Test 1:

Wafer (2) for test was arranged on a test table, and AnisotropicallyConductive Connector C1 was arranged on this Wafer (2) for test inalignment in such a manner that each of the conductive parts forconnection thereof are located on the respective electrodes to beinspected of Wafer (2) for test. Inspection Circuit Board T was thenfixed on to this Anisotropically Conductive Connector C1 in alignment insuch a manner that each of the inspection electrodes thereof are locatedon the respective conductive parts for connection of AnisotropicallyConductive Connector C1. Further, Inspection Circuit Board T waspressurized downward under a load of 124 kg.

Voltage was then successively applied to the respective inspectionelectrodes in Inspection Circuit Board T at room temperature (25° C.),and an electric resistance between an inspection electrode, to which thevoltage had been applied, and any other inspection electrode wasmeasured as an electric resistance (hereinafter referred to as“insulation resistance”) between conductive parts for connection inAnisotropically Conductive Connector C1 to count the number ofconductive parts for connection that the insulation resistance was 10 MΩor lower. Those that the insulation resistance between conductive partsfor connection is 10 MΩ or lower are difficult to be actually used inelectrical inspection as to integrated circuits formed on a wafer.

The results are shown in the following Table 2.

(8) Test 2:

Wafer (1) for test was arranged on a test table equipped with anelectric heater, and Anisotropically Conductive Connector C1 wasarranged on this Wafer (1) for test in alignment in such a manner thatthe conductive parts for connection thereof are located on therespective electrodes to be inspected of Wafer (1) for test. InspectionCircuit Board T was then arranged on this Anisotropically ConductiveConnector C1 in alignment in such a manner that the inspectionelectrodes thereof are located on the respective conductive parts forconnection of Anisotropically Conductive Connector C1. Further,Inspection Circuit Board T was pressurized downward under a load of 31kg (load applied to every conductive part for connection: about 2 g onthe average). An electric resistance between 2 inspection electrodeselectrically connected to each other through the anisotropicallyconductive connector and Wafer (1) for test among the 15,496 inspectionelectrodes in Inspection Circuit Board T was successively measured atroom temperature (25° C.) to record a half of the electric resistancevalue measured as an electric resistance (hereinafter referred to as“conduction resistance”) of the conductive part for connection inAnisotropically Conductive Connector C1, thereby counting the number ofconductive parts for connection that the conduction resistance was 1 Ωor higher. The above-described process is referred to as “Process 1”.

After a load for pressurizing the circuit board for inspection was thenchanged to 126 kg (load applied to every conductive part for connection:about 8 g on the average), the test table was heated to 125° C. Afterthe temperature of the test table became stable, the conductionresistance of the conductive parts for connection in AnisotropicallyConductive Connector C1 was measured in the same manner as in Process 1to count the number of conductive parts for connection that theconduction resistance was 1 Ω or higher. Thereafter, the test table wasleft to stand for 1 hour in this state. The above-described process isreferred to as “Process 2”.

After the test table was cooled to room temperature, the pressureagainst the circuit board for inspection was released. Theabove-described process is referred to as “Process 3”.

The above-described Processes 1, 2 and 3 were regarded as a cycle, andthe cycle was continuously repeated 500 times in total.

In the above-described test, those that the conduction resistance of theconductive parts for connection is 1 Ω or higher are difficult to beactually used in electrical inspection of integrated circuits formed ona wafer.

The results are shown in the following Table 3.

(9) Test 3:

A conduction resistance of the conductive parts for connection wasmeasured in the same manner as in Test 2 except that Sheet-likeConnector M was arranged on Wafer (1) for test arranged on the testtable in alignment in such a manner that the front-surface electrodeparts thereof are located on the electrodes to be inspected of Wafer (1)for test, Anisotropically Conductive Connector C1 was arranged onSheet-like Connector M in alignment in such a manner that the conductiveparts for connection thereof are located on the back-surface electrodeparts in Sheet-like Connector M, and Inspection Circuit Board T waspressurized downward under a load of 62 kg (load applied to everyconductive part for connection: about 4 g on the average), thereby thenumber of conductive parts for connection that the conduction resistancewas 1 Ω or higher was counted.

The results are shown in the following Table 4.

EXAMPLE 2

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (2) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC2”. In this Anisotropically Conductive Connector C2, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (2)is 6.0.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C2 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1, Test 2 and Test 3 were conducted in the same manner as inExample 1 except that Anisotropically Conductive Connector C2 was usedin place of Anisotropically Conductive Connector C1. The results areshown in the following Tables 2, 3 and 4.

EXAMPLE 3

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (3) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC3”. In this Anisotropically Conductive Connector C3, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (3)is 6.5.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C3 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1, Test 2 and Test 3 were conducted in the same manner as inExample 1 except that Anisotropically Conductive Connector C3 was usedin place of Anisotropically Conductive Connector C1. The results areshown in the following Tables 2, 3 and 4.

EXAMPLE 4

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (4) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC4”. In this Anisotropically Conductive Connector C4, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (4)is 5.8.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C4 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1, Test 2 and Test 3 were conducted in the same manner as inExample 1 except that Anisotropically Conductive Connector C4 was usedin place of Anisotropically Conductive Connector C1. The results areshown in the following Tables 2, 3 and 4.

EXAMPLE 5

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (5) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC5”. In this Anisotropically Conductive Connector C5, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (5)is 3.4.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C5 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1, Test 2 and Test 3 were conducted in the same manner as inExample 1 except that Anisotropically Conductive Connector C5 was usedin place of Anisotropically Conductive Connector C1. The results areshown in the following Tables 2, 3 and 4.

COMPARATIVE EXAMPLE 1

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (6) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC6”. In this Anisotropically Conductive Connector C6, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (6)is 2.6.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C6 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1 was conducted in the same manner as in Example 1 except thatAnisotropically Conductive Connector C6 was used in place ofAnisotropically Conductive Connector C1. The results are shown in thefollowing Table 2.

COMPARATIVE EXAMPLE 2

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (7) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC7”. In this Anisotropically Conductive Connector C7, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (7)is 9.4.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C7 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1, Test 2 and Test 3 were conducted in the same manner as inExample 1 except that Anisotropically Conductive Connector C7 was usedin place of Anisotropically Conductive Connector C1. The results areshown in the following Tables 2, 3 and 4.

COMPARATIVE EXAMPLE 3

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (8) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC8”. In this Anisotropically Conductive Connector C8, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (8)is 11.9.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C8 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1, Test 2 and Test 3 were conducted in the same manner as inExample 1 except that Anisotropically Conductive Connector C8 was usedin place of Anisotropically Conductive Connector C1. The results areshown in the following Tables 2, 3 and 4.

COMPARATIVE EXAMPLE 4

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (9) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC9”. In this Anisotropically Conductive Connector C9, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (9)is 15.6.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C9 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1, Test 2 and Test 3 were conducted in the same manner as inExample 1 except that Anisotropically Conductive Connector C9 was usedin place of Anisotropically Conductive Connector C1. The results areshown in the following Tables 2, 3 and 4.

COMPARATIVE EXAMPLE 5

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (10) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC10”. In this Anisotropically Conductive Connector C10, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (10)is 5.2.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C10 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1, Test 2 and Test 3 were conducted in the same manner as inExample 1 except that Anisotropically Conductive Connector C10 was usedin place of Anisotropically Conductive Connector C1. The results areshown in the following Tables 2, 3 and 4.

COMPARATIVE EXAMPLE 6

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (11) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC11”. In this Anisotropically Conductive Connector C11, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (11)is 2.6.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C11 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1 was conducted in the same manner as in Example 1 except thatAnisotropically Conductive Connector C11 was used in place ofAnisotropically Conductive Connector C1. The results are shown in thefollowing Table 2.

COMPARATIVE EXAMPLE 7

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (12) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC12”. In this Anisotropically Conductive Connector C12, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (12)is 8.8.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C12 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1, Test 2 and Test 3 were conducted in the same manner as inExample 1 except that Anisotropically Conductive Connector C12 was usedin place of Anisotropically Conductive Connector C1. The results areshown in the following Tables 2, 3 and 4.

COMPARATIVE EXAMPLE 8

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (13) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC13”. In this Anisotropically Conductive Connector C13, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (13)is 8.9.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C13 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1, Test 2 and Test 3 were conducted in the same manner as inExample 1 except that Anisotropically Conductive Connector C13 was usedin place of Anisotropically Conductive Connector C1. The results areshown in the following Tables 2, 3 and 4.

COMPARATIVE EXAMPLE 9

An anisotropically conductive connector was produced in the same manneras in Example 1 except that Conductive Particles (14) were used in placeof Conductive Particles (1). This anisotropically conductive connectorwill hereinafter be referred to as “Anisotropically Conductive ConnectorC14”. In this Anisotropically Conductive Connector C14, the value of aratio W/Dn of the shortest width W of the conductive part for connectionto the number average particle diameter Dn of Conductive Particles (14)is 5.4.

The content of the conductive particles in the conductive parts forconnection in each of the elastic anisotropically conductive films ofAnisotropically Conductive Connector C14 thus obtained was investigated.As a result, the content was about 30% in terms of a volume fraction inall the conductive parts for connection.

The parts to be supported and the insulating parts in the functionalparts of the elastic anisotropically conductive films were observed. Asa result, it was confirmed that the conductive particles are present inthe parts to be supported and that the conductive particles are scarcelypresent in the insulating parts in the functional parts.

Test 1 was conducted in the same manner as in Example 1 except thatAnisotropically Conductive Connector C14 was used in place ofAnisotropically Conductive Connector C1. The results are shown in thefollowing Table 2. TABLE 2 Number of Number of conductive partsconductive parts for connection for connection that insulation thatinsulation resistance was resistance was 10 MΩ or lower 10 MΩ or lowerExample 1 0 Comparative 42 Example 3 Example 2 0 Comparative 168 Example4 Example 3 0 Comparative 210 Example 5 Example 4 0 Comparative 822Example 6 Example 5 6 Comparative 28 Example 7 Comparative 946Comparative 22 Example 1 Example 8 Comparative 36 Comparative 694Example 2 Example 9

TABLE 3 Number of conductive parts for connection that conductionresistance was 1 Ω or higher (count) Number of cycles 1 20 50 100 200300 400 500 Example 1 Room temperature, 0 0 0 0 0 0 0 0 31 Kg 125° C.,126 kg 0 0 0 0 0 0 0 0 Example 2 Room temperature, 0 0 0 0 0 0 0 0 31 Kg125° C., 126 kg 0 0 0 0 0 0 0 0 Example 3 Room temperature, 0 0 0 0 0 00 0 31 Kg 125° C., 126 kg 0 0 0 0 0 0 0 0 Example 4 Room temperature, 00 0 0 0 0 0 0 31 Kg 125° C., 126 kg 0 0 0 0 0 0 0 0 Example 5 Roomtemperature, 0 0 0 0 16 40 224 564 31 Kg 125° C., 126 kg 0 0 0 0 2 16 76196 Comparative Room temperature, 0 14 198 652 6826 — — — Example 2 31Kg 125° C., 126 kg 0 4 65 214 2078 — — — Comparative Room temperature,12 136 516 1694 — — — — Example 3 31 Kg 125° C., 126 kg 4 26 176 9856012 — — — Comparative Room temperature, 128 358 784 2326 — — — —Example 4 31 Kg 125° C., 126 kg 36 98 286 1262 6424 — — — ComparativeRoom temperature, 0 46 462 1426 — — — — Example 5 31 Kg 125° C., 126 kg0 28 188 526 3956 — — — Comparative Room temperature, 0 0 72 368 10082830 — — Example 7 31 Kg 125° C., 126 kg 0 0 30 210 426 1564 6234 —Comparative Room temperature, 0 0 32 562 2864 — — — Example 8 31 Kg 125°C., 126 kg 0 0 12 354 1620 5892 — —

TABLE 4 Number of conductive parts for connection that conductionresistance was 1 Ω or higher (count) Number of cycles 1 20 50 100 200300 400 500 Example 1 Room temperature, 0 0 0 0 0 0 0 0 62 Kg 125° C.,126 kg 0 0 0 0 0 0 0 0 Example 2 Room temperature, 0 0 0 0 0 0 0 0 62 Kg125° C., 126 kg 0 0 0 0 0 0 0 0 Example 3 Room temperature, 0 0 0 0 0 00 0 62 Kg 125° C., 126 kg 0 0 0 0 0 0 0 0 Example 4 Room temperature, 00 0 0 0 0 0 0 62 Kg 125° C., 126 kg 0 0 0 0 0 0 0 0 Example 5 Roomtemperature, 0 0 0 0 10 26 150 382 62 Kg 125° C., 126 kg 0 0 0 0 2 16 74168 Comparative Room temperature, 0 10 134 442 3966 — — — Example 2 62Kg 125° C., 126 kg 0 6 64 212 1658 — — — Comparative Room temperature, 032 236 1152 6898 — — — Example 3 62 Kg 125° C., 126 kg 0 14 178 602 3452— — — Comparative Room temperature, 4 48 392 1462 6762 — — — Example 462 Kg 125° C., 126 kg 0 30 286 856 4834 — — — Comparative Roomtemperature, 0 28 198 982 5632 — — — Example 5 62 Kg 125° C., 126 kg 018 162 588 3016 — — — Comparative Room temperature, 0 22 68 336 590 2016— — Example 7 62 Kg 125° C., 126 kg 0 6 26 196 384 1326 5864 —Comparative Room temperature, 0 0 32 562 2864 — — — Example 8 62 Kg 125°C., 126 kg 0 0 12 354 1620 4970 — —

As apparent from the results shown in Tables 2 to 4, it was confirmedthat according to Anisotropically Conductive Connector C1 toAnisotropically Conductive Connector C5 of Example 1 to Example 5, goodconductivity is achieved in the conductive parts for connection in theelastic anisotropically conductive films, and sufficient insulatingproperty is achieved between adjacent conductive parts for connectioneven when the pitch of the conductive parts for connection is small, agood electrically connected state is stably retained even withenvironmental changes such as thermal hysteresis by temperature change,and good conductivity is retained over a long period of time even whenit is used repeatedly under a high-temperature environment.

EFFECTS OF THE INVENTION

According to the anisotropically conductive connectors of the presentinvention, the number average particle diameter of the conductiveparticles falls within the specific range in the relation to theshortest width of the conductive part for connection, and thecoefficient of variation of particle diameter is at most 50%, so thatthe conductive particles are those having a particle diameter proper forforming the conductive parts for connection. Accordingly, the conductiveparticles are prevented from remaining in a great amount at portions tobecome the insulating parts in the molding material layer when amagnetic field is applied to the molding material layer in the formationof the elastic anisotropically conductive films, a necessary amount ofthe conductive particles can be gathered in a state accommodated inportions to become the conductive parts for connection, and moreover thenumber of the conductive particles arranged in the thickness-wisedirection can be lessened. As a result, good conductivity is achieved asto all the conductive parts for connection formed, and sufficientinsulating property is surely achieved between adjacent conductive partsfor connection. In addition, since the coating layer formed of ahigh-conductive metal and having a proper thickness can be formed on theconductive particles, it is inhibited to lower the conductivity of theconductive particles at the surfaces thereof even when theanisotropically conductive connectors are used repeatedly under ahigh-temperature environment, whereby it is prevented to markedlyincrease the total sum of contact resistance among the conductiveparticles in a conductive path formed in the conductive part forconnection, and so the necessary conductivity can be retained over along period of time.

According to the anisotropically conductive connectors of the presentinvention for wafer inspection, such effects as described below areadditionally brought about in addition to the above-described effects.

Namely, since the part to be supported is formed at the peripheral edgeof the functional part having the conductive parts for connection ineach of the elastic anisotropically conductive films, and this part tobe supported is fixed to the periphery about the anisotropicallyconductive film-arranging hole in the frame plate, the anisotropicallyconductive connectors are hard to be deformed and easy to handle, sothat the positioning and the holding and fixing to a wafer, which is anobject of inspection, can be easily conducted in an electricallyconnecting operation to the wafer.

Since the respective anisotropically conductive film-arranging holes inthe frame plate are formed correspondingly to electrode regions, inwhich electrodes to be inspected have been formed, of integratedcircuits in a wafer, which is an object of inspection, and the elasticanisotropically conductive film arranged in each of the anisotropicallyconductive film-arranging holes may be small in area, the individualelastic anisotropically conductive films are easy to be formed. Inaddition, since the elastic anisotropically conductive film small inarea is little in the absolute quantity of thermal expansion in a planedirection of the elastic anisotropically conductive film even when it issubjected to thermal hysteresis, the thermal expansion of the elasticanisotropically conductive film in the plane direction is surelyrestrained by the frame plate by using a material having a lowcoefficient of linear thermal expansion as that for forming the frameplate. Accordingly, a good electrically connected state can be stablyretained even when the WLBI test is performed on a large-area wafer.

According to the conductive paste compositions of the present invention,the elastic anisotropically conductive films in the above-describedanisotropically conductive connectors can be advantageously formed.

According to the probe members of the present invention, positioning,and holding and fixing to a wafer, which is an object of inspection, canbe conducted with ease in an electrically connecting operation to thewafer, and moreover high connection reliability to respective electrodesto be inspected is achieved, and the necessary conductivity can beretained over a long period of time even when they are used repeatedlyunder a high-temperature environment.

According to the wafer inspection apparatus and wafer inspection methodof the present invention, electrical connection to electrodes to beinspected of a wafer, which is an object of inspection, is achievedthrough the probe member, so that positioning, and holding and fixing tothe wafer can be conducted with ease even when the pitch of theelectrodes to be inspected is small. In addition, high connectionreliability to respective electrodes to be inspected is achieved, andthe necessary electrical inspection can be stably performed over a longperiod of time even when the apparatus is used repeatedly in a testunder a high-temperature environment.

Since inspection can be conducted with high reliability according to thewafer inspection method of the present invention, integrated circuitshaving defects or latent defects can be sorted at high probability fromamong a great number of integrated circuits formed on a wafer, wherebysemiconductor integrated circuit devices having defects or latentdefects can be removed in a production process of semiconductorintegrated circuit devices to surely provide non-defective productsalone.

The wafer inspection method according to the present invention isapplied to an inspection step in a production process of semiconductorintegrated circuit devices, whereby productivity of the semiconductorintegrated circuit devices can be improved. In addition, probabilitythat semiconductor integrated circuit devices having defects or latentdefects are included in mass-produced semiconductor integrated circuitdevices can be reduced. Accordingly, according to a semiconductorintegrated circuit device obtained by such a production process, highreliability is achieved in an electronic instrument that is a finalproduct, into which the semiconductor integrated circuit devices areincorporated. In addition, since the incorporation of a semiconductorintegrated circuit device having defects or latent defects into theelectronic instrument that is a final product can be prevented at highprobability, the frequency of occurance of trouble in the resultingelectronic instrument by long-term service can be reduced.

1. (canceled)
 2. An anisotropically conductive connector forelectrically connecting the circuit board for inspection to a wafer bybeing arranged on the surface of the circuit board for inspection forconducting electrical inspection of each of a plurality of integratedcircuits formed on the wafer in a state of the wafer, which comprises: aframe plate, in which a plurality of anisotropically conductivefilm-arranging holes each extending in a thickness-wise direction of theframe plate have been formed correspondingly to electrode regions, inwhich electrodes to be inspected have been arranged, in all or part ofthe integrated circuits formed on the wafer, which is an object ofinspection, and a plurality of elastic anisotropically conductive filmsarranged in the respective anisotropically conductive film-arrangingholes in this frame plate and each supported by the peripheral edgeabout the anisotropically conductive film-arranging hole, wherein eachof the elastic anisotropically conductive films is composed of afunctional part having a plurality of conductive parts for connectioncontaining conductive particles exhibiting magnetism at a high densityand extending in the thickness-wise direction of the film, and arrangedcorrespondingly to the electrodes to be inspected in the integratedcircuits formed on the wafer, which is the object of inspection, and aninsulating part mutually insulating these conductive parts forconnection, and a part to be supported integrally formed at a peripheraledge of the functional part and fixed to the peripheral edge about theanisotropically conductive film-arranging hole in the frame plate,wherein supposing that the shortest width of each of the conductiveparts for connection is W, and the number average particle diameter ofthe conductive particles is Dn, a value of a ratio W/Dn of the shortestwidth of the conductive part for connection to the number averageparticle diameter of the conductive particles falls within a range of 3to 8, and a coefficient of variation of particle diameter of theconductive particles is at most 50%, wherein supposing that the weightaverage particle diameter of the conductive particles is Dw, a value ofa ratio Dw/Dn of the weight average particle diameter to the numberaverage particle diameter is at most 5, and wherein the number averageparticle diameter of the conductive particles is 3 to 30 μm. 3.(canceled)
 4. (canceled)
 5. The anisotropically conductive connectoraccording to claim 2, wherein the conductive particles are thosesubjected to a classification treatment by an air classifier.
 6. Theanisotropically conductive connector according to claim 2 or 5, whereinthe conductive particles are those obtained by coating surfaces of coreparticles exhibiting magnetism with a high-conductive metal.
 7. Theanisotropically conductive connector according to any one of claims 2, 5and 6, wherein the coefficient of linear thermal expansion of the frameplate is at most 3×10⁻⁵/K.
 8. A conductive paste composition suitablefor forming the elastic anisotropically conductive films in theanisotropically conductive connector according to any one of claims 2and 5 to 7, which comprises curable liquid silicone rubber andconductive particles exhibiting magnetism, wherein supposing that theshortest width of each of the conductive parts for connection in theelastic anisotropically conductive film is W, and the number averageparticle diameter of the conductive particles is Dn, a value of a ratioW/Dn of the shortest width of the conductive part for connection to thenumber average particle diameter of the conductive particles fallswithin a range of 3 to 8, and a coefficient of variation of particlediameter of the conductive particles is at most 50%.
 9. A probe membersuitable for use in conducting electrical inspection of each of aplurality of integrated circuits formed on a wafer in a state of thewafer, which comprises: a circuit board for inspection, on the surfaceof which inspection electrodes have been formed in accordance with apattern corresponding to a pattern of electrodes to be inspected of theintegrated circuits formed on the wafer, which is an object ofinspection, and the anisotropically conductive connector according toany one of claims 2 and 5 to 7, which is arranged on the surface of thecircuit board for inspection.
 10. The probe member according to claim 9,wherein the coefficient of linear thermal expansion of the frame platein the anisotropically conductive connector is at most 3×10⁻⁵/K, and thecoefficient of linear thermal expansion of a base material making up thecircuit board for inspection is at most 3×10⁻⁵/K.
 11. The probe memberaccording to claim 9 or 10, wherein a sheet-like connector composed ofan insulating sheet and a plurality of electrode structures eachextending through in a thickness-wise direction of the insulating sheetand arranged in accordance with a pattern corresponding to the patternof the electrodes to be inspected is arranged on the anisotropicallyconductive connector.
 12. A wafer inspection apparatus for conductingelectrical inspection of each of a plurality of integrated circuitsformed on a wafer in a state of the wafer, which comprises the probemember according to any one of claims 9 to 11, wherein electricalconnection to the integrated circuits formed on the wafer, which is anobject of inspection, is achieved through the probe member.
 13. A waferinspection method comprising electrically connecting each of a pluralityof integrated circuits formed on a wafer to a tester through the probemember according to any one of claims 9 to 11 to perform electricalinspection of the integrated circuits formed on the wafer.